Microorganisms and methods for production of specific length fatty alcohols and related compounds

ABSTRACT

The invention provides non-naturally occurring microbial organisms containing a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organisms selectively produce a fatty alcohol, fatty aldehyde or fatty acid of a specified length. Also provided are non-naturally occurring microbial organisms having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organisms further include an acetyl-CoA pathway. In some aspects, the microbial organisms of the invention have select gene disruptions or enzyme attenuations that increase production of fatty alcohols, fatty aldehydes or fatty acids. The invention additionally provides methods of using the above microbial organisms to produce a fatty alcohol, a fatty aldehyde or a fatty acid.

This application claims the benefit of priority of U.S. Provisional application Ser. No. 61/714,144, filed Oct. 15, 2012, the entire contents of which is incorporated herein by reference.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted in ASCII format via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Jul. 13, 2016, is named SEQLIST_12956-210-999.txt and is 18,505 bytes in size.

BACKGROUND OF THE INVENTION

The present invention relates generally to biosynthetic processes, and more specifically to organisms having specific length fatty alcohol, fatty aldehyde or fatty acid biosynthetic capacity.

Primary alcohols are a product class of compounds having a variety of industrial applications which include a variety of biofuels and specialty chemicals. Primary alcohols also can be used to make a large number of additional industrial products including polymers and surfactants. For example, higher primary alcohols, also known as fatty alcohols (C₄-C₂₄) and their ethoxylates are used as surfactants in many consumer detergents, cleaning products and personal care products worldwide such as laundry powders and liquids, dishwashing liquid and hard surface cleaners. They are also used in the manufacture of a variety of industrial chemicals and in lubricating oil additives. Specific length fatty alcohols, such as octanol and hexanol, have useful organoleptic properties and have long been employed as fragrance and flavor materials. Smaller chain length C₄-C₈ alcohols (e.g., butanol) are used as chemical intermediates for production of derivatives such as acrylates used in paints, coatings, and adhesives applications.

Fatty alcohols are currently produced from, for example, hydrogenation of fatty acids, hydroformylation of terminal olefins, partial oxidation of n-paraffins and the Al-catalyzed polymerization of ethylene. Unfortunately, it is not commercially viable to produce fatty alcohols directly from the oxidation of petroleum-based linear hydrocarbons (n-paraffins). This impracticality is because the oxidation of n-paraffins produces primarily secondary alcohols, tertiary alcohols or ketones, or a mixture of these compounds, but does not produce high yields of fatty alcohols. Additionally, currently known methods for producing fatty alcohols suffer from the disadvantage that they are restricted to feedstock which is relatively expensive, notably ethylene, which is produced via the thermal cracking of petroleum. In addition, current methods require several steps, and several catalyst types.

Fatty alcohol production by microorganisms involves fatty acid synthesis followed by acyl-reduction steps. The universal fatty acid biosynthesis pathway found in most cells has been investigated for production of fatty alcohols and other fatty acid derivatives. There is currently a great deal of improvement that can be achieved to provide more efficient biosynthesis pathways for fatty alcohol production with significantly higher theoretical product and energy yields.

Thus, there exists a need for alternative means for effectively producing commercial quantities of fatty alcohols. The present invention satisfies this need and provides related advantages as well.

SUMMARY OF INVENTION

The invention provides non-naturally occurring microbial organisms containing fatty alcohol, fatty aldehyde or fatty acid pathways. In some embodiments, the non-naturally occurring microbial organism of the invention has a malonyl-CoA independent fatty acyl-CoA elongation (MI-FAE) cycle and a termination pathway as depicted in FIGS. 1, 6 and 7, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce a fatty alcohol, fatty aldehyde or fatty acid of Formula (I):

wherein R₁ is C₁₋₂₄ linear alkyl; R₂ is CH₂OH, CHO, or COOH; R₃ is H, OH, or oxo (═O); and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four, wherein the substrate of each of said enzymes of the MI-FAE cycle and the termination pathway are independently selected from a compound of Formula (II), propionyl-CoA or acetyl-CoA:

wherein R₁ is C₁₋₂₄ linear alkyl; R₃ is H, OH, or oxo (═O); R₄ is S—CoA, ACP, OH or H; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; wherein said one or more enzymes of the MI-FAE cycle are each selective for a compound of Formula (II) having a number of carbon atoms at R₁ that is no greater than the number of carbon atoms at R₁ of said compound of Formula (I), and wherein said one or more enzymes of the termination pathway are each selective for a compound of Formula (II) having a number of carbon atoms at R₁ that is no less than the number of carbon atoms at R₁ of said compound of Formula (I).

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organism further includes an acetyl-CoA pathway and at least one exogenous nucleic acid encoding an acetyl-CoA pathway enzyme expressed in a sufficient amount to produce acetyl-CoA, wherein the acetyl-CoA pathway includes a pathway shown in FIG. 2, 3, 4 or 5.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organism has one or more gene disruptions, wherein the one or more gene disruptions occur in endogenous genes encoding proteins or enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by the microbial organism, the one or more gene disruptions confer increased production of a fatty alcohol, fatty aldehyde or fatty acid in the microbial organism.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein one or more enzymes of the MI-FAE cycle or the termination pathway preferentially react with an NADH cofactor or have reduced preference for reacting with an NAD(P)H cofactor.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organism has one or more gene disruptions in genes encoding proteins or enzymes that result in an increased ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism following the disruptions.

In some embodiments, the non-naturally occurring microbial organism of the invention is Crabtree positive and is in culture medium comprising excess glucose. In such conditions, as described herein, the microbial organism can result in increasing the ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organism has at least one exogenous nucleic acid encoding an extracellular transporter or an extracellular transport system for a fatty alcohol, fatty aldehyde or fatty acid of the invention.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organism one or more endogenous enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by said microbial organism, has attenuated enzyme activity or expression levels.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organism has attenuated enzyme activity or expression levels for one or more endogenous enzymes involved in the oxidation of NAD(P)H or NADH.

The invention additionally provides methods of using the above microbial organisms to produce a fatty alcohol, a fatty aldehyde or a fatty acid by culturing a non-naturally occurring microbial organism containing a fatty alcohol, fatty aldehyde or fatty acid pathway under conditions and for a sufficient period of time to produce a fatty alcohol, fatty aldehyde or fatty acid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary MI-FAE cycle in combination with termination pathways for production of fatty alcohols, aldehydes, or acids from the acyl-CoA intermediate of the MI-FAE cycle. Enzymes are: A. Thiolase; B. 3-Oxoacyl-CoA reductase; C. 3-Hydroxyacyl-CoA dehydratase; D. Enoyl-CoA reductase; E. Acyl-CoA reductase (aldehyde forming); F. Alcohol dehydrogenase; G. Acyl-CoA reductase (alcohol forming); H. acyl-CoA hydrolase, transferase or synthase; J. Acyl-ACP reductase; K. Acyl-CoA:ACP acyltransferase; L. Thioesterase; and N. Aldehyde dehydrogenase (acid forming) or carboxylic acid reductase.

FIG. 2 shows exemplary pathways for production of cytosolic acetyl-CoA from pyruvate or threonine. Enzymes are: A. pyruvate oxidase (acetate-forming); B. acetyl-CoA synthetase, ligase or transferase; C. acetate kinase; D. phosphotransacetylase; E. pyruvate decarboxylase; F. acetaldehyde dehydrogenase; G. pyruvate oxidase (acetyl-phosphate forming); H. pyruvate dehydrogenase, pyruvate:ferredoxin oxidoreductase, pyruvate:NAD(P)H oxidoreductase or pyruvate formate lyase; I. acetaldehyde dehydrogenase (acylating); and J. threonine aldolase.

FIG. 3 shows exemplary pathways for production of acetyl-CoA from phosphoenolpyruvate (PEP). Enzymes are: A. PEP carboxylase or PEP carboxykinase; B. oxaloacetate decarboxylase; C. malonate semialdehyde dehydrogenase (acetylating); D. acetyl-CoA carboxylase or malonyl-CoA decarboxylase; F. oxaloacetate dehydrogenase or oxaloacetate oxidoreductase; G. malonate semialdehyde dehydrogenase (acylating); H. pyruvate carboxylase; J. malonate semialdehyde dehydrogenase; K. malonyl-CoA synthetase or transferase; L. malic enzyme; M. malate dehydrogenase or oxidoreductase; and N. pyruvate kinase or PEP phosphatase.

FIG. 4 shows exemplary pathways for production of cytosolic acetyl-CoA from mitochondrial acetyl-CoA using citrate and malate transporters. Enzymes are: A. citrate synthase; B. citrate transporter; C. citrate/malate transporter; D. ATP citrate lyase; E. citrate lyase; F. acetyl-CoA synthetase or transferase; H. cytosolic malate dehydrogenase; I. malate transporter; J. mitochondrial malate dehydrogenase; K. acetate kinase; and L. phosphotransacetylase.

FIG. 5 shows exemplary pathways for production of cytosolic acetyl-CoA from mitochondrial acetyl-CoA using citrate and oxaloacetate transporters. Enzymes are: A. citrate synthase; B. citrate transporter; C. citrate/oxaloacetate transporter; D. ATP citrate lyase; E. citrate lyase; F. acetyl-CoA synthetase or transferase; G) oxaloacetate transporter; K) acetate kinase; and L) phosphotransacetylase.

FIG. 6 shows an exemplary MI-FAE cycle for elongating the linear alkyl of R₁. Enzymes are: A. Thiolase; B. 3-Ketoacyl-CoA reductase; C. 3-Hydroxyacyl-CoA dehydratase; and D. Enoyl-CoA reductase;

FIG. 7 shows an exemplary termination cycle for generating a fatty alcohol, fatty aldehyde or fatty acid from any of the MI-FAE cycle intermediates of FIG. 6. Enzymes are: E. MI-FAE intermediate-CoA reductase (aldehyde forming); F. Alcohol dehydrogenase; G. MI-FAE intermediate-CoA reductase (alcohol forming); H. MI-FAE intermediate-CoA hydrolase, transferase or synthase; J. MI-FAE intermediate-ACP reductase; K. MI-FAE intermediate-CoA:ACP acyltransferase; L. Thioesterase; and N. Aldehyde dehydrogenase (acid forming) or carboxylic acid reductase. R1 is C1-24 linear alkyl; R₃ is H, OH, or oxo (═O) and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four.

FIG. 8 shows exemplary compounds that can be produced from the four MI-FAE cycle intermediates using the cycle depicted in FIG. 6 and the termination pathways depicted in FIG. 7. R is C₁₋₂₄ linear alkyl.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “non-naturally occurring” when used in reference to a microbial organism or microorganism of the invention is intended to mean that the microbial organism has at least one genetic alteration not normally found in a naturally occurring strain of the referenced species, including wild-type strains of the referenced species. Genetic alterations include, for example, modifications introducing expressible nucleic acids encoding metabolic polypeptides, other nucleic acid additions, nucleic acid deletions and/or other functional disruption of the microbial organism's genetic material. Such modifications include, for example, coding regions and functional fragments thereof, for heterologous, homologous or both heterologous and homologous polypeptides for the referenced species. Additional modifications include, for example, non-coding regulatory regions in which the modifications alter expression of a gene or operon. Exemplary metabolic polypeptides include enzymes or proteins within a fatty alcohol, fatty aldehyde or fatty alcohol biosynthetic pathway.

A metabolic modification refers to a biochemical reaction that is altered from its naturally occurring state. Therefore, non-naturally occurring microorganisms can have genetic modifications to nucleic acids encoding metabolic polypeptides, or functional fragments thereof. Exemplary metabolic modifications are disclosed herein.

As used herein, the term “isolated” when used in reference to a microbial organism is intended to mean an organism that is substantially free of at least one component as the referenced microbial organism is found in nature. The term includes a microbial organism that is removed from some or all components as it is found in its natural environment. The term also includes a microbial organism that is removed from some or all components as the microbial organism is found in non-naturally occurring environments. Therefore, an isolated microbial organism is partly or completely separated from other substances as it is found in nature or as it is grown, stored or subsisted in non-naturally occurring environments. Specific examples of isolated microbial organisms include partially pure microbes, substantially pure microbes and microbes cultured in a medium that is non-naturally occurring.

As used herein, the terms “microbial,” “microbial organism” or “microorganism” are intended to mean any organism that exists as a microscopic cell that is included within the domains of archaea, bacteria or eukarya. Therefore, the term is intended to encompass prokaryotic or eukaryotic cells or organisms having a microscopic size and includes bacteria, archaea and eubacteria of all species as well as eukaryotic microorganisms such as yeast and fungi. The term also includes cell cultures of any species that can be cultured for the production of a biochemical.

As used herein, the term “CoA” or “coenzyme A” is intended to mean an organic cofactor or prosthetic group (nonprotein portion of an enzyme) whose presence is required for the activity of many enzymes (the apoenzyme) to form an active enzyme system. Coenzyme A functions in certain condensing enzymes, acts in acetyl or other acyl group transfer and in fatty acid synthesis and oxidation, pyruvate oxidation and in other acetylation.

As used herein, the term “ACP” or “acyl carrier protein” refers to any of the relatively small acidic proteins that are associated with the fatty acid synthase system of many organisms, from bacteria to plants. ACPs can contain one 4′-phosphopantetheine prosthetic group bound covalently by a phosphate ester bond to the hydroxyl group of a serine residue. The sulfhydryl group of the 4′-phosphopantetheine moiety serves as an anchor to which acyl intermediates are (thio)esterified during fatty-acid synthesis. An example of an ACP is Escherichia coli ACP, a separate single protein, containing 77 amino-acid residues (8.85 kDa), wherein the phosphopantetheine group is linked to serine 36.

As used herein, the term “substantially anaerobic” when used in reference to a culture or growth condition is intended to mean that the amount of oxygen is less than about 10% of saturation for dissolved oxygen in liquid media. The term also is intended to include sealed chambers of liquid or solid medium maintained with an atmosphere of less than about 1% oxygen.

“Exogenous” as it is used herein is intended to mean that the referenced molecule or the referenced activity is introduced into the host microbial organism. The molecule can be introduced, for example, by introduction of an encoding nucleic acid into the host genetic material such as by integration into a host chromosome or as non-chromosomal genetic material such as a plasmid. Therefore, the term as it is used in reference to expression of an encoding nucleic acid refers to introduction of the encoding nucleic acid in an expressible form into the microbial organism. When used in reference to a biosynthetic activity, the term refers to an activity that is introduced into the host reference organism. The source can be, for example, a homologous or heterologous encoding nucleic acid that expresses the referenced activity following introduction into the host microbial organism. Therefore, the term “endogenous” refers to a referenced molecule or activity that is present in the host. Similarly, the term when used in reference to expression of an encoding nucleic acid refers to expression of an encoding nucleic acid contained within the microbial organism. The term “heterologous” refers to a molecule or activity derived from a source other than the referenced species whereas “homologous” refers to a molecule or activity derived from the host microbial organism. Accordingly, exogenous expression of an encoding nucleic acid of the invention can utilize either or both a heterologous or homologous encoding nucleic acid.

It is understood that when more than one exogenous nucleic acid is included in a microbial organism that the more than one exogenous nucleic acids refers to the referenced encoding nucleic acid or biosynthetic activity, as discussed above. It is further understood, as disclosed herein, that such more than one exogenous nucleic acids can be introduced into the host microbial organism on separate nucleic acid molecules, on polycistronic nucleic acid molecules, or a combination thereof, and still be considered as more than one exogenous nucleic acid. For example, as disclosed herein a microbial organism can be engineered to express two or more exogenous nucleic acids encoding a desired pathway enzyme or protein. In the case where two exogenous nucleic acids encoding a desired activity are introduced into a host microbial organism, it is understood that the two exogenous nucleic acids can be introduced as a single nucleic acid, for example, on a single plasmid, on separate plasmids, can be integrated into the host chromosome at a single site or multiple sites, and still be considered as two exogenous nucleic acids. Similarly, it is understood that more than two exogenous nucleic acids can be introduced into a host organism in any desired combination, for example, on a single plasmid, on separate plasmids, can be integrated into the host chromosome at a single site or multiple sites, and still be considered as two or more exogenous nucleic acids, for example three exogenous nucleic acids. Thus, the number of referenced exogenous nucleic acids or biosynthetic activities refers to the number of encoding nucleic acids or the number of biosynthetic activities, not the number of separate nucleic acids introduced into the host organism.

As used herein, the term “gene disruption,” or grammatical equivalents thereof, is intended to mean a genetic alteration that renders the encoded gene product inactive or attenuated. The genetic alteration can be, for example, deletion of the entire gene, deletion of a regulatory sequence required for transcription or translation, deletion of a portion of the gene which results in a truncated gene product, or by any of various mutation strategies that inactivate or attenuate the encoded gene product. One particularly useful method of gene disruption is complete gene deletion because it reduces or eliminates the occurrence of genetic reversions in the non-naturally occurring microorganisms of the invention. The phenotypic effect of a gene disruption can be a null mutation, which can arise from many types of mutations including inactivating point mutations, entire gene deletions, and deletions of chromosomal segments or entire chromosomes. Specific enzyme inhibitors, such as antibiotics, can also produce null mutant phenotype, therefore being equivalent to gene disruption.

As used herein, the term “growth-coupled” when used in reference to the production of a biochemical product is intended to mean that the biosynthesis of the referenced biochemical product is produced during the growth phase of a microorganism. In a particular embodiment, the growth-coupled production can be obligatory, meaning that the biosynthesis of the referenced biochemical is an obligatory product produced during the growth phase of a microorganism.

As used herein, the term “attenuate,” or grammatical equivalents thereof, is intended to mean to weaken, reduce or diminish the activity or amount of an enzyme or protein. Attenuation of the activity or amount of an enzyme or protein can mimic complete disruption if the attenuation causes the activity or amount to fall below a critical level required for a given pathway to function. However, the attenuation of the activity or amount of an enzyme or protein that mimics complete disruption for one pathway, can still be sufficient for a separate pathway to continue to function. For example, attenuation of an endogenous enzyme or protein can be sufficient to mimic the complete disruption of the same enzyme or protein for production of a fatty alcohol, fatty aldehyde or fatty acid product of the invention, but the remaining activity or amount of enzyme or protein can still be sufficient to maintain other pathways, such as a pathway that is critical for the host microbial organism to survive, reproduce or grow. Attenuation of an enzyme or protein can also be weakening, reducing or diminishing the activity or amount of the enzyme or protein in an amount that is sufficient to increase yield of a fatty alcohol, fatty aldehyde or fatty acid product of the invention, but does not necessarily mimic complete disruption of the enzyme or protein.

The term “fatty alcohol,” as used herein, is intended to mean an aliphatic compound that contains one or more hydroxyl groups and contains a chain of 4 or more carbon atoms. The fatty alcohol possesses the group —CH₂OH that can be oxidized so as to form a corresponding aldehyde or acid having the same number of carbon atoms. A fatty alcohol can also be a saturated fatty alcohol, an unsaturated fatty alcohol, a 1,3-diol, or a 3-oxo-alkan-1-ol. Exemplary fatty alcohols include a compound of Formula (III)-(VI):

wherein R₁ is a C₁₋₂₄ linear alkyl.

The term “fatty aldehyde,” as used herein, is intended to mean an aliphatic compound that contains an aldehyde (CHO) group and contains a chain of 4 or more carbon atoms. The fatty aldehyde can be reduced to form the corresponding alcohol or oxidized to form the carboxylic acid having the same number of carbon atoms. A fatty aldehyde can also be a saturated fatty aldehyde, an unsaturated fatty aldehyde, a 3-hydroxyaldehyde or 3-oxoaldehyde. Exemplary fatty aldehydes include a compound of Formula (VII)-(X):

wherein R₁ is a C₁₋₂₄ linear alkyl.

The term “fatty acid,” as used herein, is intended to mean an aliphatic compound that contains a carboxylic acid group and contains a chain of 4 or more carbon atoms. The fatty acid can be reduced to form the corresponding alcohol or aldehyde having the same number of carbon atoms. A fatty acid can also be a saturated fatty acid, an unsaturated fatty acid, a 3-hydroxyacid or a 3-oxoacids. Exemplary fatty acids include a compound of Formula (XI)-(XIV):

wherein R₁ is a C₁₋₂₄ linear alkyl.

The term “alkyl” refers to a linear saturated monovalent hydrocarbon. The alkyl can be a linear saturated monovalent hydrocarbon that has 1 to 24 (C₁₋₂₄), 1 to 17 (C₁₋₁₇), or 9 to 13 (C₉₋₁₃) carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl. For example, C₉₋₁₃ alkyl refers to a linear saturated monovalent hydrocarbon of 9 to 13 carbon atoms.

The invention disclosed herein is based, at least in part, on recombinant microorganisms capable of synthesizing fatty alcohols, fatty aldehydes, or fatty acids using a malonyl-CoA-independent fatty acid elongation (MI-FAE) cycle and a termination pathway. In some embodiments, the microorganisms of the invention can utilize a heterologous MI-FAE cycle coupled with an acyl-CoA termination pathway to form fatty alcohols, fatty aldehydes, or fatty acids. The MI-FAE cycle can include a thiolase, a 3-oxoacyl-CoA reductase, a 3-hydroxyacyl-CoA dehydratase and an enoyl-CoA reductase. Each passage through the MI-FAE cycle results in the formation of an acyl-CoA elongated by a single two carbon unit compared to the acyl-CoA substrate entering the elongation cycle. Products can be even or odd chain length, depending on the initial substrate entering the acyl-CoA elongation pathway, i.e. two acety-CoA substrates or one acetyl-CoA substrate combined with a propionyl-CoA substrate. Elongation of the two acetyl-CoA substrates produces an even chain length product, whereas elongation with the propionyl-CoA substrate produces an odd chain length product. A termination pathway catalyzes the conversion of a MI-FAE intermediate, such as the acyl-CoA, to its corresponding fatty alcohol, fatty aldehyde, or fatty acid product. MI-FAE cycle and termination pathway enzymes can be expressed in one or more compartments of the microorganism. For example, in one embodiment, all MI-FAE cycle and termination pathway enzymes are expressed in the cytosol. Additionally, the microorganisms of the invention can be engineered to optionally secret the desired product into the culture media or fermentation broth for further manipulation or isolation.

Products of the invention include fatty alcohols, fatty aldehydes, or fatty acids derived from intermediates of the MI-FAE elongation cycle. For example, alcohol products can include saturated fatty alcohols, unsaturated fatty alcohols, 1,3-diols, and 3-oxo-alkan-1-ols. Aldehyde products can include saturated fatty aldehydes, unsaturated fatty aldehydes, 3-hydroxyaldehydes and 3-oxoaldehydes. Acid products can include saturated fatty acids, unsaturated fatty acids, 3-hydroxyacids and 3-oxoacids. These products can further be converted to derivatives such as fatty esters, either by chemical or enzymatic means. Methods for converting fatty alcohols to esters are well known in the art.

The invention also encompasses fatty alcohol, fatty aldehyde, and fatty acid chain-length control strategies in conjunction with host strain engineering strategies, such that the non-naturally occurring microorganism of the invention efficiently directs carbon and reducing equivalents toward fermentation products of a specific chain length.

Recombinant microorganisms of the invention can produce commercial quantities of a fatty alcohol, fatty aldehyde, or fatty acid ranging in chain length from four carbon atoms (C₄) to twenty-four carbon atoms (C₂₄) or more carbon atoms. The microorganism of the invention can produce a desired product that is at least 50%, 60%, 70%, 75%, 85%, 90%, 95% or more selective for a particular chain length. The carbon chain-length of the product is controlled by one or more enzymes of the MI-FAE cycle (steps A/B/C/D of FIG. 6) in combination with one or more termination pathway enzymes (steps E-N of FIG. 7). Chain length can be capped during the elongation cycle by one or more MI-FAE cycle enzymes (thiolase, 3-oxoacyl-CoA reductase, 3-hydroxyacyl-CoA dehydratase and/or enoyl-CoA reductase) exhibiting selectivity for MI-FAE cycle substrates having a number of carbon atoms that are no greater than the desired product size. Chain length can be further constrained by one or more enzymes catalyzing the conversion of the MI-FAE cycle intermediate to the fatty alcohol, fatty aldehyde or fatty acid product such that the one or more termination enzymes only reacts with substrates having a number of carbon atoms that are no less than the desired fatty alcohol, fatty aldehyde or fatty acid product.

The termination pathway enzymes catalyzing conversion of a MI-FAE-CoA intermediate to a fatty alcohol can include combinations of a fatty acyl-CoA reductase (alcohol or aldehyde forming), a fatty aldehyde reductase, an acyl-ACP reductase, an acyl-CoA:ACP acyltransferase, a thioesterase, an acyl-CoA hydrolase and/or a carboxylic acid reductase (pathways G; E/F; K/J/F; H/N/F; or K/L/N/F of FIG. 7). Termination pathway enzymes for converting a MI-FAE-CoA intermediate to a fatty acid can include combinations of a thioesterase, a CoA hydrolase, an acyl-CoA:ACP acyltransferase, an aldehyde dehydrogenase and/or an acyl-ACP reductase (pathways H; K/L; E/N; K/J/N of FIG. 7). For production of a fatty aldehyde, the termination pathway enzymes can include combinations of a fatty acyl-CoA reductase (aldehyde forming), an acyl-ACP reductase, an acyl-CoA:ACP acyltransferase, a thioesterase, an acyl-CoA hydrolase and/or a carboxylic acid reductase (pathways E; K/J; H/N; or K/L/N of FIG. 7).

The non-naturally occurring microbial organisms of the invention can also efficiently direct cellular resources, including carbon, energy and reducing equivalents, to the production of fatty alcohols, fatty aldehydes and fatty acids, thereby resulting in improved yield, productivity and/or titer relative to a naturally occurring organism. In one embodiment, the microorganism is modified to increase cytosolic acetyl-CoA levels. In another embodiment, the microorganism is modified to efficiently direct cytosolic acyl-CoA into fatty alcohols, fatty aldehydes or fatty acids rather than other byproducts or cellular processes. Enzymes or pathways that lead to the formation of byproducts can be attenuated or deleted. Exemplary byproducts include, but are not limited to, ethanol, glycerol, lactate, acetate, esters and carbon dioxide. Additional byproducts can include fatty-acyl-CoA derivatives such as alcohols, alkenes, alkanes, esters, acids and aldehydes. Accordingly, a byproduct can include any fermentation product diverting carbon and/or reducing equivalents from the product of interest.

In another embodiment, the availability of reducing equivalents or redox ratio is increased. In yet another embodiment, the cofactor requirements of the microorganism are balanced such that the same reduced cofactors generated during carbon assimilation and central metabolism are utilized by MI-FAE cycle and/or termination pathway enzymes. In yet another embodiment, the fatty alcohol, fatty aldehyde or fatty acid producing organism expresses a transporter which exports the fatty alcohol, fatty aldehyde or fatty acid from the cell.

Microbial organisms capable of fatty alcohol production are exemplified herein with reference to the Saccharomyces cerevisaie genetic background. However, with the complete genome sequence available now for thousands of species (with more than half of these available on public databases such as the NCBI), the identification of an alternate species homolog for one or more genes, including for example, orthologs, paralogs and nonorthologous gene displacements, and the interchange of genetic alterations between eukaryotic organisms is routine and well known in the art. Accordingly, the metabolic alterations enabling production of fatty alcohols described herein with reference to a particular organism such as Saccharomyces cerevisiae can be readily applied to other microorganisms. Given the teachings and guidance provided herein, those skilled in the art understand that a metabolic alteration exemplified in one organism can be applied equally to other organisms.

The methods of the invention are applicable to various prokaryotic and eukaryotic organisms such as bacteria, yeast and fungus. For example, the yeast can include Saccharomyces cerevisiae and Rhizopus arrhizus. Exemplary eukaryotic organisms can also include Crabtree positive and negative yeasts, and yeasts in the genera Saccharomyces, Kluyveromyces, Candida or Pichia. Further exemplary eukaryotic species include those selected from Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces marxianus, Aspergillus terreus, Aspergillus niger, Rhizopus arrhizus, Rhizopus oryzae, Candida albicans, Candida boidinii, Candida sonorensis, Candida tropicalis, Yarrowia lipolytica and Pichia pastoris. Additionally, select cells from larger eukaryotic organisms are also applicable to methods of the present invention. Exemplary bacteria include species selected from Escherichia coli, Klebsiella oxytoca, Anaerobiospirillum succiniciproducens, Actinobacillus succinogenes, Mannheimia succiniciproducens, Rhizobium etli, Bacillus subtilis, Corynebacterium glutamicum, Gluconobacter oxydans, Zymomonas mobilis, Lactococcus lactis, Lactobacillus plantarum, Streptomyces coelicolor, Clostridium acetobutylicum, Pseudomonas fluorescens, and Pseudomonas putida.

In some aspects of the invention, production of fatty alcohols, fatty aldehydes and fatty acids through the modified pathways disclosed herein are particularly useful because the pathways result in higher product and ATP yields than through naturally occurring biosynthetic pathways such as the well-known malonyl-CoA dependent fatty acid synthesis pathway. Using acetyl-CoA as a C₂ extension unit instead of malonyl-acyl carrier protein (malonyl-ACP) saves one ATP molecule per unit flux of acetyl-CoA entering the MI-FAE cycle. The MI-FAE cycle results in acyl-CoA instead of acyl-ACP, and can preclude the need of the ATP-consuming acyl-CoA synthase reactions for the production of octanol and other fatty alcohols, fatty aldehydes or fatty acids. The fatty alcohol, fatty aldehyde and fatty acid producing organisms of the invention can additionally allow the use of biosynthetic processes to convert low cost renewable feedstock for the manufacture of chemical products.

The eukaryotic organism of the invention can be further engineered to metabolize and/or co-utilize a variety of feedstocks including glucose, xylose, fructose, syngas, methanol, and the like.

Chain length control can be achieved using a combination of highly active enzymes with suitable substrate ranges appropriate for biosynthesis of the desired fatty alcohol, fatty aldehyde, or fatty acid. Chain length of the product can be controlled using one or more enzymes of MI-FAE cycle or termination pathway. As described herein, chain length can be capped during the MI-FAE cycle by one or more MI-FAE cycle enzymes (thiolase, 3-oxoacyl-CoA reductase, 3-hydroxyacyl-CoA dehydratase and/or enoyl-CoA reductase) exhibiting selectivity for MI-FAE cycle substrates having a number of carbon atoms that are no greater than the desired product size. Since enzymes are reversible, any of the elongation pathway enzymes can serve in this capacity. Selecting enzymes with broad substrate ranges but defined chain-length boundaries enables the use of a single enzyme to catalyze multiple cycles of elongation, while conferring product specificity. To further hone specificity and prevent the accumulation of shorter byproducts, selectivity is further constrained by product-forming termination enzymes, such that one or more enzymes are selective for acyl-CoA or other termination pathway substrates having a number of carbon atoms that are no less than the desired chain length. The deletion or attenuation of endogenous pathway enzymes that produce different chain length products can further hone product specificity.

Using the approaches outlined herein, one skilled in the art can select enzymes from the literature with characterized substrate ranges that selectively produce a fatty alcohol, fatty aldehyde or fatty acid product of a specific chain length. To selectively produce fatty alcohols, fatty aldehydes or fatty acids of a desired length, one can utilize combinations of known enzymes in the literature with different selectivity ranges as described above. For example, a non-naturally occurring microbial organism that produces C₁₆ fatty alcohol can express enzymes such as the Rattus norvegicus Acaa1a thiolase and the enoyl-CoA reductase of Mycobacterium smegmatis, which only accept substrates up to length C₁₆. Coupling one or both chain elongation enzymes with a C₁₆-C₁₈ fatty acyl-CoA reductase (alcohol or aldehyde forming) such as FAR of Simmondsia chinensis further increases product specificity by reducing the synthesis of shorter alcohol products. As another example, a non-naturally occurring microbial organism of the invention can selectively produce alcohols of length C₁₄ by combining the 3-hydroxyacyl-CoA dehydratase of Arabidopsis thaliana with the acyl-CoA reductase Acr1 of Acinetobacter sp. Strain M-1. To produce 3-oxoacids of length C₁₄, one can, for example, combine the rat thiolase with the 3-oxoacyl-CoA hydrolase of Solanum lycopersicum. As still a further example, to produce C₁₈ fatty acids, one can combine the Salmonella enterica fadE enoyl-CoA reductase with the tesB thioesterase of E. coli. In yet another example, selective production of C₆ alcohols are formed by combining the paaH1 thiolase from Ralstonia eutropha with the Leifsonia sp. S749 alcohol dehydrogenase lsadh.

Exemplary MI-FAE cycle and termination pathway enzymes are described in detail in Example I. The biosynthetic enzymes described herein exhibit varying degrees of substrate specificity. Exemplary substrate ranges of enzymes characterized in the literature are shown in the table below and described in further detail in Example I.

Pathway Chain step length Gene Organism 1A C4 atoB Escherichia coli 1A C6 phaD Pseudomonas putida 1A C6-C8 bktB Ralstonia eutropha 1A C10-C16 Acaa1a Rattus norvegicus 1B C4 hbd Clostridium acetobutylicum 1B C4-C6 paaH1 Ralstonia eutropha 1B C4-C10 HADH Sus scrofa 1B C4-C18 fadB Escherichia coli 1C C4-C6 crt Clostridium acetobutylicum 1C C4-C7 pimF Rhodopseudomonas palustris 1C C4-C14 MFP2 Arabidopsis thaliana 1D C4-C6 ECR1 Euglena gracilis 1D C6-C8 ECR3 Euglena gracilis 1D C8-10 ECR2 Euglena gracilis 1D C8-C16 ECR Rattus norvegicus 1D C10-C16 ECR Mycobacterium smegmatis 1D C2-C18 fadE Salmonella enterica 1E C2-C4 bphG Pseudomonas sp 1E C4 Bld Clostridium saccharoperbutylacetonicum 1E C12-C20 ACR Acinetobacter calcoaceticus 1E C14-C18 Acr1 Acinetobacter sp. Strain M-1 1E C16-C18 Rv1543, Rv3391 Mycobacterium tuberculosis 1F C6-C7 lsadh Leifsonia sp. S749 1F C2-C8 yqhD Escherichia coli 1F C3-C10 Adh Pseudomonas putida 1F C2-C14 alrA Acinetobacter sp. strain M-1 1F C2-C30 ADH1 Geobacillus thermodenitrificans 1G C2 adhE Escherichia coli 1G C2-C8 adhe2 Clostridium acetobutylicum 1G C14-C16 At3g11980 Arabidopsis thaliana 1G C16 At3g44560 Arabidopsis thaliana 1G C16-C18 FAR Simmondsia chinensis 1H C4 Cat2 Clostridium kluyveri 1H C4-C6 Acot12 Rattus norvegicus 1H C14 MKS2 Solanum lycopersicum 1L C8-C10 fatB2 Cuphea hookeriana 1L C12 fatB Umbellularia california 1L C14-C16 fatB3 Cuphea hookeriana 1L C18 tesA Escherichia coli 1N C12-C18 Car Nocardia iowensis 1N C12-C16 Car Mycobacterium sp. (strain JLS)

Taking into account the differences in chain-length specificities of each enzyme in the MI-FAE cycle, one skilled in the art can select one or more enzymes for catalyzing each elongation cycle reaction step (steps A-D of FIG. 6). For example, for the thiolase step of the MI-FAE cycle, some thiolase enzymes such as bktB of Ralstonia eutropha catalyze the elongation of short- and medium-chain acyl-CoA intermediates (C₆-C₈), whereas others such as Acaa1a of R. norvegicus are active on longer-chain substrates (C₁₀-C₁₆). Thus, an microbial organism producing a fatty alcohol, fatty aldehyde or fatty acid can comprise one, two, three, four or more variants of a thiolase, 3-oxoacyl-CoA reductase, 3-hydroxyacyl-CoA dehydratase and/or enoyl-CoA reductase.

Chain length specificity of enzymes can be assayed by methods well known in the art (eg. Wrensford et al, Anal Biochem 192:49-54 (1991)). The substrate ranges of fatty alcohol, fatty aldehyde, or fatty acid producing enzymes can be further extended or narrowed by methods well known in the art. Variants of biologically-occurring enzymes can be generated, for example, by rational and directed evolution, mutagenesis and enzyme shuffling as described herein. As one example, a rational engineering approach for altering chain length specificity was taken by Denic and Weissman (Denic and Weissman, Cell 130:663-77 (2008)). Denic and Weissman mapped the region of the yeast elongase protein ELOp responsible for chain length, and introduced mutations to vary the length of fatty acid products. In this instance, the geometry of the hydrophobic substrate pocket set an upper boundary on chain length. A similar approach can be useful for altering the chain length specificities of enzymes of the MI-FAE cycle and/or termination pathways.

Enzyme mutagenesis, expression in a host, and screening for fatty alcohol production is another useful approach for generating enzyme variants with improved properties for the desired application. For example, US patent application 2012/0009640 lists hundreds of variants of Marinobacter algicola and Marinobacter aquaeolei FAR enzymes with improved activity over the wild type enzyme, and varying product profiles.

Enzyme mutagenesis (random or directed) in conjunction with a selection platform is another useful approach. For example, Machado and coworkers developed a selection platform aimed at increasing the activity of acyl-CoA elongation cycle enzymes on longer chain length substrates (Machado et al., Met Eng in press (2012)). Machado et al. identified the chain-length limiting step of their pathway (a 3-hydroxyacyl-CoA dehydrogenase) and evolved it for improved activity on C₆-C₈ substrates using an anaerobic growth rescue platform. Additional variants of enzymes useful for producing fatty alcohols are listed in the table below.

Protein/ GenBankID/ Enzyme GI number Organism Variant(s) Reference 3-Ketoacyl-CoA Acaa2 Rattus norvegicus H352A, H352E, Zeng et al., Prot. Expr. Purif. 35: 320-326 thiolase NP_569117.1 H352K, H352Y (2004) GI: 18426866 3-Hydroxyacyl- Hadh Rattus norvegicus S137A, S137C, Liu et al., Prot. Expr. Purif. 37: 344-351 CoA NP_476534.1 S137T (2004). dehydrogenase GI: 17105336 Enoyl-CoA Ech1 Rattus norvegicus E144A, Kiema et al., Biochem. 38: 2991-2999 hydratase NP_072116.1 E144A/Q162L, (1999) GI: 12018256 E164A, Q162A, Q162L, Q162M Enoyl-CoA InhA Mycobacterium tuberculosis K165A, Poletto, S. et al., Prot. Expr. Purif. 34: reductase AAY54545.1 K165Q, Y158F 118-125 (2004). GI: 66737267 Acyl-CoA LuxC Photobacterium phosphoreum C171S, C279S, Lee, C. et al., Biochim. Biophys. Acta. reductase AAT00788.1 C286S 1338: 215-222 (1997). GI: 46561111 Alcohol YADH-1 Saccharomyces cerevisiae D223G, D49N, Leskovac et al., FEMS Yeast Res. dehydrogenase P00330.4 E68Q, G204A, 2(4): 481-94 (2002). GI: 1168350 G224I, H47R, H51E, L203A Fatty alcohol AdhE Escherichia coli A267T/E568K, Membrillo et al., J. Biol. Chem. 275(43): forming acyl-CoA NP_415757.1 A267T 333869-75 (2000). reductase (FAR) GI: 16129202

Those skilled in the art will understand that the genetic alterations, including metabolic modifications exemplified herein, are described with reference to a suitable host organism such as E. coli or S. cerevisiae and their corresponding metabolic reactions or a suitable source organism for desired genetic material such as genes for a desired metabolic pathway. However, given the complete genome sequencing of a wide variety of organisms and the high level of skill in the area of genomics, those skilled in the art will readily be able to apply the teachings and guidance provided herein to essentially all other organisms. For example, the metabolic alterations exemplified herein can readily be applied to other species by incorporating the same or analogous encoding nucleic acid from species other than the referenced species. Such genetic alterations include, for example, genetic alterations of species homologs, in general, and in particular, orthologs, paralogs or nonorthologous gene displacements.

An ortholog is a gene or genes that are related by vertical descent and are responsible for substantially the same or identical functions in different organisms. For example, mouse epoxide hydrolase and human epoxide hydrolase can be considered orthologs for the biological function of hydrolysis of epoxides. Genes are related by vertical descent when, for example, they share sequence similarity of sufficient amount to indicate they are homologous, or related by evolution from a common ancestor. Genes can also be considered orthologs if they share three-dimensional structure but not necessarily sequence similarity, of a sufficient amount to indicate that they have evolved from a common ancestor to the extent that the primary sequence similarity is not identifiable. Genes that are orthologous can encode proteins with sequence similarity of about 25% to 100% amino acid sequence identity. Genes encoding proteins sharing an amino acid similarity less that 25% can also be considered to have arisen by vertical descent if their three-dimensional structure also shows similarities. Members of the serine protease family of enzymes, including tissue plasminogen activator and elastase, are considered to have arisen by vertical descent from a common ancestor.

Orthologs include genes or their encoded gene products that through, for example, evolution, have diverged in structure or overall activity. For example, where one species encodes a gene product exhibiting two functions and where such functions have been separated into distinct genes in a second species, the three genes and their corresponding products are considered to be orthologs. For the production of a biochemical product, those skilled in the art will understand that the orthologous gene harboring the metabolic activity to be introduced or disrupted is to be chosen for construction of the non-naturally occurring microorganism. An example of orthologs exhibiting separable activities is where distinct activities have been separated into distinct gene products between two or more species or within a single species. A specific example is the separation of elastase proteolysis and plasminogen proteolysis, two types of serine protease activity, into distinct molecules as plasminogen activator and elastase. A second example is the separation of mycoplasma 5′-3′ exonuclease and Drosophila DNA polymerase III activity. The DNA polymerase from the first species can be considered an ortholog to either or both of the exonuclease or the polymerase from the second species and vice versa.

In contrast, paralogs are homologs related by, for example, duplication followed by evolutionary divergence and have similar or common, but not identical functions. Paralogs can originate or derive from, for example, the same species or from a different species. For example, microsomal epoxide hydrolase (epoxide hydrolase I) and soluble epoxide hydrolase (epoxide hydrolase II) can be considered paralogs because they represent two distinct enzymes, co-evolved from a common ancestor, that catalyze distinct reactions and have distinct functions in the same species. Paralogs are proteins from the same species with significant sequence similarity to each other suggesting that they are homologous, or related through co-evolution from a common ancestor. Groups of paralogous protein families include HipA homologs, luciferase genes, peptidases, and others.

A nonorthologous gene displacement is a nonorthologous gene from one species that can substitute for a referenced gene function in a different species. Substitution includes, for example, being able to perform substantially the same or a similar function in the species of origin compared to the referenced function in the different species. Although generally, a nonorthologous gene displacement will be identifiable as structurally related to a known gene encoding the referenced function, less structurally related but functionally similar genes and their corresponding gene products nevertheless will still fall within the meaning of the term as it is used herein. Functional similarity requires, for example, at least some structural similarity in the active site or binding region of a nonorthologous gene product compared to a gene encoding the function sought to be substituted. Therefore, a nonorthologous gene includes, for example, a paralog or an unrelated gene.

Therefore, in identifying and constructing the non-naturally occurring microbial organisms of the invention having fatty alcohol, fatty aldehyde or fatty acid biosynthetic capability, those skilled in the art will understand with applying the teaching and guidance provided herein to a particular species that the identification of metabolic modifications can include identification and inclusion or inactivation of orthologs. To the extent that paralogs and/or nonorthologous gene displacements are present in the referenced microorganism that encode an enzyme catalyzing a similar or substantially similar metabolic reaction, those skilled in the art also can utilize these evolutionally related genes. Similarly for a gene disruption, evolutionally related genes can also be disrupted or deleted in a host microbial organism to reduce or eliminate functional redundancy of enzymatic activities targeted for disruption.

Orthologs, paralogs and nonorthologous gene displacements can be determined by methods well known to those skilled in the art. For example, inspection of nucleic acid or amino acid sequences for two polypeptides will reveal sequence identity and similarities between the compared sequences. Based on such similarities, one skilled in the art can determine if the similarity is sufficiently high to indicate the proteins are related through evolution from a common ancestor. Algorithms well known to those skilled in the art, such as Align, BLAST, Clustal W and others compare and determine a raw sequence similarity or identity, and also determine the presence or significance of gaps in the sequence which can be assigned a weight or score. Such algorithms also are known in the art and are similarly applicable for determining nucleotide sequence similarity or identity. Parameters for sufficient similarity to determine relatedness are computed based on well known methods for calculating statistical similarity, or the chance of finding a similar match in a random polypeptide, and the significance of the match determined. A computer comparison of two or more sequences can, if desired, also be optimized visually by those skilled in the art. Related gene products or proteins can be expected to have a high similarity, for example, 25% to 100% sequence identity. Proteins that are unrelated can have an identity which is essentially the same as would be expected to occur by chance, if a database of sufficient size is scanned (about 5%). Sequences between 5% and 24% may or may not represent sufficient homology to conclude that the compared sequences are related. Additional statistical analysis to determine the significance of such matches given the size of the data set can be carried out to determine the relevance of these sequences.

Exemplary parameters for determining relatedness of two or more sequences using the BLAST algorithm, for example, can be as set forth below. Briefly, amino acid sequence alignments can be performed using BLASTP version 2.0.8 (Jan. 5, 1999) and the following parameters: Matrix: 0 BLOSUM62; gap open: 11; gap extension: 1; x_dropoff: 50; expect: 10.0; wordsize: 3; filter: on. Nucleic acid sequence alignments can be performed using BLASTN version 2.0.6 (Sep. 16, 1998) and the following parameters: Match: 1; mismatch: −2; gap open: 5; gap extension: 2; x_dropoff: 50; expect: 10.0; wordsize: 11; filter: off. Those skilled in the art will know what modifications can be made to the above parameters to either increase or decrease the stringency of the comparison, for example, and determine the relatedness of two or more sequences.

In some embodiments, the invention provides a non-naturally occurring microbial organism having a MI-FAE cycle and a termination pathway, wherein the MI-FAE cycle includes one or more thiolase, one or more 3-oxoacyl-CoA reductase, one or more 3-hydroxyacyl-CoA dehydratase, and one or more enoyl-CoA reductase, wherein the termination pathway includes a pathway shown in FIG. 1, 6 or 7 selected from: (1) 1H; (2) 1K and 1L; (3) 1E and 1N; (4) 1K, 1J, and 1N; (5) 1E; (6) 1K and 1J; (7) 1H and 1N; (8) 1K, 1L, and 1N; (9) 1E and 1F; (10) 1K, 1J, and 1F; (11) 1H, 1N, and 1F; (12) 1K, 1L, 1N, and 1F; and (13) 1G, wherein 1E is an acyl-CoA reductase (aldehyde forming), wherein 1F is an alcohol dehydrogenase, wherein 1G is an acyl-CoA reductase (alcohol forming), wherein 1H is an acyl-CoA hydrolase, acyl-CoA transferase or acyl-CoA synthase, wherein 1J is an acyl-ACP reductase, wherein 1K is an acyl-CoA:ACP acyltransferase, wherein 1L is a thioesterase, wherein 1N is an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce a compound of Formula (I):

wherein R₁ is C₁₋₂₄ linear alkyl; R₂ is CH₂OH, CHO, or COOH; R₃ is H, OH, or oxo (═O); and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four, wherein the substrate of each of said enzymes of the MI-FAE cycle and the termination pathway are independently selected from a compound of Formula (II), propionyl-CoA or acetyl-CoA:

wherein R₁ is C₁₋₂₄ linear alkyl; R₃ is H, OH, or oxo (═O); R₄ is S—CoA, ACP, OH or H; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; wherein said one or more enzymes of the MI-FAE cycle are each selective for a compound of Formula (II) having a number of carbon atoms at R₁ that is no greater than the number of carbon atoms at R₁ of said compound of Formula (I), and wherein said one or more enzymes of the termination pathway are each selective for a compound of Formula (II) having a number of carbon atoms at R₁ that is no less than the number of carbon atoms at R₁ of said compound of Formula (I).

In some aspects of the invention, non-naturally occurring microbial organism of the invention can produce a compound of Formula (I) wherein R₁ is C₁₋₁₇ linear alkyl. In another aspect of the invention, the R₁ of the compound of Formula (I) is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some aspects of the invention, the microbial organism microbial organism includes two, three, or four exogenous nucleic acids each encoding an enzyme of the MI-FAE cycle. In some aspects of the invention, the microbial organism includes two, three, or four exogenous nucleic acids each encoding an enzyme of the termination pathway. In some aspects of the invention, the microbial organism includes exogenous nucleic acids encoding each of the enzymes of at least one of the pathways selected from (1)-(13). In some aspects, the at least one exogenous nucleic acid is a heterologous nucleic acid. In some aspects, the non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

In some embodiments, the invention provides a non naturally occurring microbial organism, wherein the one or more enzymes of the MI-FAE cycle or termination pathway is expressed in a sufficient amount to produce a fatty alcohol selected from the Formulas (III)-(VI):

wherein R₁ is C₁₋₂₄ linear alkyl, or alternatively R₁ is C₁₋₁₇ linear alkyl, or alternatively R₁ is C₉₋₁₃ linear alkyl. In some aspects of the invention, R₁ is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some embodiments, the invention provides a non naturally occurring microbial organism, wherein the one or more enzymes of the MI-FAE cycle or termination pathway is expressed in a sufficient amount to produce a fatty aldehyde selected from the Formula (VII)-(X):

wherein R₁ is C₁₋₂₄ linear alkyl, or alternatively R₁ is C₁₋₁₇ linear alkyl, or alternatively R₁ is C₉₋₁₃ linear alkyl. In some aspects of the invention, R₁ is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some embodiments, the invention provides a non naturally occurring microbial organism, wherein the one or more enzymes of the MI-FAE cycle or termination pathway is expressed in a sufficient amount to produce a fatty acid selected from the Formula (XI)-(XIV):

wherein R₁ is C₁₋₂₄ linear alkyl, or alternatively R₁ is C₁₋₁₇ linear alkyl, or alternatively R₁ is C₉₋₁₃ linear alkyl. In some aspects of the invention, R₁ is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some embodiments, the invention provides a non-naturally occurring microbial organism as described herein, wherein the microbial organism further includes an acetyl-CoA pathway and at least one exogenous nucleic acid encoding an acetyl-CoA pathway enzyme expressed in a sufficient amount to produce acetyl-CoA, wherein the acetyl-CoA pathway includes a pathway shown in FIG. 2, 3, 4 or 5 selected from: (1) 2A and 2B; (2) 2A, 2C, and 2D; (3) 2H; (4) 2G and 2D; (5) 2E, 2F and 2B; (6) 2E and 2I; (7) 2J, 2F and 2B; (8) 2J and 2I; (9) 3A, 3B, and 3C; (10) 3A, 3B, 3J, 3K, and 3D; (11) 3A, 3B, 3G, and 3D; (12) 3A, 3F, and 3D; (13) 3N, 3H, 3B and 3C; (14) 3N, 3H, 3B, 3J, 3K, and 3D; (15) 3N, 3H, 3B, 3G, and 3D; (16) 3N, 3H, 3F, and 3D; (17) 3L, 3M, 3B and 3C; (18) 3L, 3M, 3B, 3J, 3K, and 3D; (19) 3L, 3M, 3B, 3G, and 3D; (20) 3L, 3M, 3F, and 3D; (21) 4A, 4B, 4D, 4H, 4I, and 4J; (22) 4A, 4B, 4E, 4F, 4H, 4I, and 4J; (23) 4A, 4B, 4E, 4K, 4L, 4H, 4I, and 4J; (24) 4A, 4C, 4D, 4H, and 4J; (25) 4A, 4C, 4E, 4F, 4H, and 4J; (26) 4A, 4C, 4E, 4K, 4L, 4H, and 4J; (27) 5A, 5B, 5D, and 5G; (28) 5A, 5B, 5E, 5F, and 5G; (29) 5A, 5B, 5E, 5K, 5L, and 5G; (30) 5A, 5C, and 5D; (31) 5A, 5C, 5E, and 5F; and (32) 5A, 5C, 5E, 5K, and 5L, wherein 2A is a pyruvate oxidase (acetate-forming), wherein 2B is an acetyl-CoA synthetase, an acetyl-CoA ligase or an acetyl-CoA transferase, wherein 2C is an acetate kinase, wherein 2D is a phosphotransacetylase, wherein 2E is a pyruvate decarboxylase, wherein 2F is an acetaldehyde dehydrogenase, wherein 2G is a pyruvate oxidase (acetyl-phosphate forming), wherein 2H is a pyruvate dehydrogenase, a pyruvate:ferredoxin oxidoreductase, a pyruvate:NAD(P)H oxidoreductase or a pyruvate formate lyase, wherein 2I is an acetaldehyde dehydrogenase (acylating), wherein 2J is a threonine aldolase, wherein 3A is a phosphoenolpyruvate (PEP) carboxylase or a PEP carboxykinase, wherein 3B is an oxaloacetate decarboxylase, wherein 3C is a malonate semialdehyde dehydrogenase (acetylating), wherein 3D is an acetyl-CoA carboxylase or a malonyl-CoA decarboxylase, wherein 3F is an oxaloacetate dehydrogenase or an oxaloacetate oxidoreductase, wherein 3G is a malonate semialdehyde dehydrogenase (acylating), wherein 3H is a pyruvate carboxylase, wherein 3J is a malonate semialdehyde dehydrogenase, wherein 3K is a malonyl-CoA synthetase or a malonyl-CoA transferase, wherein 3L is a malic enzyme, wherein 3M is a malate dehydrogenase or a malate oxidoreductase, wherein 3N is a pyruvate kinase or a PEP phosphatase, wherein 4A is a citrate synthase, wherein 4B is a citrate transporter, wherein 4C is a citrate/malate transporter, wherein 4D is an ATP citrate lyase, wherein 4E is a citrate lyase, wherein 4F is an acetyl-CoA synthetase or an acetyl-CoA transferase, wherein 4H is a cytosolic malate dehydrogenase, wherein 4I is a malate transporter, wherein 4J is a mitochondrial malate dehydrogenase, wherein 4K is an acetate kinase, wherein 4L is a phosphotransacetylase, wherein 5A is a citrate synthase, wherein 5B is a citrate transporter, wherein 5C is a citrate/oxaloacetate transporter, wherein 5D is an ATP citrate lyase, wherein 5E is a citrate lyase, wherein 5F is an acetyl-CoA synthetase or an acetyl-CoA transferase, wherein 5G is an oxaloacetate transporter, wherein 5K is an acetate kinase, and wherein 5L is a phosphotransacetylase.

In some aspects, the microbial organism of the invention can include two, three, four, five, six, seven or eight exogenous nucleic acids each encoding an acetyl-CoA pathway enzyme. In some aspects, the microbial organism includes exogenous nucleic acids encoding each of the acetyl-CoA pathway enzymes of at least one of the pathways selected from (1)-(32).

In an additional embodiment, the invention provides a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the non-naturally occurring microbial organism comprises at least one exogenous nucleic acid encoding an enzyme or protein that converts a substrate to a product selected from the group consisting of two acetyl-CoA molecules to a 3-ketoacyl-CoA, acetyl-CoA plus propionyl-CoA to a ketoacyl-CoA, a 3-ketoacyl-CoA to a 3-hydroxyacyl-CoA, a 3-hydroxyacyl-CoA to an enoyl-CoA, an enoyl-CoA to an acyl-CoA, an acyl-CoA plus an acetyl-CoA to a 3-ketoacyl-CoA, an acyl-CoA to a fatty aldehyde, a fatty aldehyde to a fatty alcohol, an acyl-CoA to a fatty alcohol, an acyl-CoA to an acyl-ACP, an acyl-ACP to a fatty acid, an acyl-CoA to a fatty acid, an acyl-ACP to a fatty aldehyde, a fatty acid to a fatty aldehyde, a fatty aldehyde to a fatty acid, pyruvate to acetate, acetate to acetyl-CoA, pyruvate to acetyl-CoA, pyruvate to acetaldehyde, threonin to acetaldehyde, acetaldehyde to acetate, acetaldehyde to acetyl-CoA, pyruvate to acetyl-phosphate, acetate to acetyl-phosphate, acetyl-phosphate to acetyl-CoA, phosphoenolpyruvate (PEP) to pyruvate, pyruvate to malate, malate to oxaloacetate, pyruvate to oxaloacetate, PEP to oxaloacetate, oxaloacetate to malonate semialdehyde, oxaloacetate to malonyl-CoA, malonate semialdehyde to malonate, malonate to malonyl-CoA, malonate semialdehyde to malonyl-CoA, malonyl-CoA to acetyl-CoA, malonate semialdehyde to acetyl-CoA, oxaloacetate plus acetyl-CoA to citrate, citrate to oxaloacetate plus acetyl-CoA, citrate to oxaloacetate plus acetate, and oxaloacetate to malate. One skilled in the art will understand that these are merely exemplary and that any of the substrate-product pairs disclosed herein suitable to produce a desired product and for which an appropriate activity is available for the conversion of the substrate to the product can be readily determined by one skilled in the art based on the teachings herein. Thus, the invention provides a non-naturally occurring microbial organism containing at least one exogenous nucleic acid encoding an enzyme or protein, where the enzyme or protein converts the substrates and products of a fatty alcohol, fatty aldehyde or fatty acid pathway, such as that shown in FIG. 1-8.

While generally described herein as a microbial organism that contains a fatty alcohol, fatty aldehyde or fatty acid pathway, it is understood that the invention additionally provides a non-naturally occurring microbial organism comprising at least one exogenous nucleic acid encoding a fatty alcohol, fatty aldehyde or fatty acid pathway enzyme or protein expressed in a sufficient amount to produce an intermediate of a fatty alcohol, fatty aldehyde or fatty acid pathway. For example, as disclosed herein, a fatty alcohol, fatty aldehyde or fatty acid pathway is exemplified in FIGS. 1-7. Therefore, in addition to a microbial organism containing a fatty alcohol, fatty aldehyde or fatty acid pathway that produces fatty alcohol, fatty aldehyde or fatty acid, the invention additionally provides a non-naturally occurring microbial organism comprising at least one exogenous nucleic acid encoding a fatty alcohol, fatty aldehyde or fatty acid pathway enzyme, where the microbial organism produces a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate, for example, a 3-ketoacyl-CoA, a 3-hydroxyacyl-CoA, an enoyl-CoA, an acyl-CoA, an acyl-ACP, acetate, acetaldehyde, acetyl-phosphate, oxaloacetate, matate, malonate semialdehyde, malonate, malonyl-CoA, acetyl-CoA, or citrate.

It is understood that any of the pathways disclosed herein, as described in the Examples and exemplified in the Figures, including the pathways of FIGS. 1-7, can be utilized to generate a non-naturally occurring microbial organism that produces any pathway intermediate or product, as desired. As disclosed herein, such a microbial organism that produces an intermediate can be used in combination with another microbial organism expressing downstream pathway enzymes to produce a desired product. However, it is understood that a non-naturally occurring microbial organism that produces a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate can be utilized to produce the intermediate as a desired product.

The invention is described herein with general reference to the metabolic reaction, reactant or product thereof, or with specific reference to one or more nucleic acids or genes encoding an enzyme associated with or catalyzing, or a protein associated with, the referenced metabolic reaction, reactant or product. Unless otherwise expressly stated herein, those skilled in the art will understand that reference to a reaction also constitutes reference to the reactants and products of the reaction. Similarly, unless otherwise expressly stated herein, reference to a reactant or product also references the reaction, and reference to any of these metabolic constituents also references the gene or genes encoding the enzymes that catalyze or proteins involved in the referenced reaction, reactant or product. Likewise, given the well known fields of metabolic biochemistry, enzymology and genomics, reference herein to a gene or encoding nucleic acid also constitutes a reference to the corresponding encoded enzyme and the reaction it catalyzes or a protein associated with the reaction as well as the reactants and products of the reaction.

The non-naturally occurring microbial organisms of the invention can be produced by introducing expressible nucleic acids encoding one or more of the enzymes or proteins participating in one or more fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathways. Depending on the host microbial organism chosen for biosynthesis, nucleic acids for some or all of a particular fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway can be expressed. For example, if a chosen host is deficient in one or more enzymes or proteins for a desired biosynthetic pathway, then expressible nucleic acids for the deficient enzyme(s) or protein(s) are introduced into the host for subsequent exogenous expression. Alternatively, if the chosen host exhibits endogenous expression of some pathway genes, but is deficient in others, then an encoding nucleic acid is needed for the deficient enzyme(s) or protein(s) to achieve fatty alcohol, fatty aldehyde or fatty acid biosynthesis. Thus, a non-naturally occurring microbial organism of the invention can be produced by introducing exogenous enzyme or protein activities to obtain a desired biosynthetic pathway or a desired biosynthetic pathway can be obtained by introducing one or more exogenous enzyme or protein activities that, together with one or more endogenous enzymes or proteins, produces a desired product such as fatty alcohol, fatty aldehyde or fatty acid.

Host microbial organisms can be selected from, and the non-naturally occurring microbial organisms generated in, for example, bacteria, yeast, fungus or any of a variety of other microorganisms applicable to fermentation processes. Exemplary bacteria include species selected from Escherichia coli, Klebsiella oxytoca, Anaerobiospirillum succiniciproducens, Actinobacillus succinogenes, Mannheimia succiniciproducens, Rhizobium etli, Bacillus subtilis, Corynebacterium glutamicum, Gluconobacter oxydans, Zymomonas mobilis, Lactococcus lactis, Lactobacillus plantarum, Streptomyces coelicolor, Clostridium acetobutylicum, Pseudomonas fluorescens, and Pseudomonas putida. Exemplary yeasts or fungi include species selected from Saccharomyces cerevisiae, Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces marxianus, Aspergillus terreus, Aspergillus niger, Pichia pastoris, Rhizopus arrhizus, Rhizobus oryzae, Yarrowia lipolytica, and the like. E. coli is a particularly useful host organism since it is a well characterized microbial organism suitable for genetic engineering. Other particularly useful host organisms include yeast such as Saccharomyces cerevisiae and Yarrowia lipolytica. It is understood that any suitable microbial host organism can be used to introduce metabolic and/or genetic modifications to produce a desired product.

Depending on the fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway constituents of a selected host microbial organism, the non-naturally occurring microbial organisms of the invention will include at least one exogenously expressed fatty alcohol, fatty aldehyde or fatty acid pathway-encoding nucleic acid and up to all encoding nucleic acids for one or more fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathways. For example, fatty alcohol, fatty aldehyde or fatty acid biosynthesis can be established in a host deficient in a pathway enzyme or protein through exogenous expression of the corresponding encoding nucleic acid. In a host deficient in all enzymes or proteins of a fatty alcohol, fatty aldehyde or fatty acid pathway, exogenous expression of all enzyme or proteins in the pathway can be included, although it is understood that all enzymes or proteins of a pathway can be expressed even if the host contains at least one of the pathway enzymes or proteins. For example, exogenous expression of all enzymes or proteins in a pathway for production of fatty alcohol, fatty aldehyde or fatty acid can be included, such as a thiolase, a 3-oxoacyl-CoA reductase, a 3-hydroxyacyl-CoA dehydratase, an enoyl-CoA redutase, an acyl-CoA reductase (aldehyde forming) and an alcohol dehydrogenase, for production of a fatty alcohol.

Given the teachings and guidance provided herein, those skilled in the art will understand that the number of encoding nucleic acids to introduce in an expressible form will, at least, parallel the fatty alcohol, fatty aldehyde or fatty acid pathway deficiencies of the selected host microbial organism. Therefore, a non-naturally occurring microbial organism of the invention can have one, two, three, four, five, six, seven or eight up to all nucleic acids encoding the enzymes or proteins constituting a fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway disclosed herein. In some embodiments, the non-naturally occurring microbial organisms also can include other genetic modifications that facilitate or optimize fatty alcohol, fatty aldehyde or fatty acid biosynthesis or that confer other useful functions onto the host microbial organism. One such other functionality can include, for example, augmentation of the synthesis of one or more of the fatty alcohol, fatty aldehyde or fatty acid pathway precursors such as acetyl-CoA or propionyl-CoA.

Generally, a host microbial organism is selected such that it produces the precursor of a fatty alcohol, fatty aldehyde or fatty acid pathway, either as a naturally produced molecule or as an engineered product that either provides de novo production of a desired precursor or increased production of a precursor naturally produced by the host microbial organism. For example, acetyl-CoA is produced naturally in a host organism such as E. coli. A host organism can be engineered to increase production of a precursor, as disclosed herein. In addition, a microbial organism that has been engineered to produce a desired precursor can be used as a host organism and further engineered to express enzymes or proteins of a fatty alcohol, fatty aldehyde or fatty acid pathway.

In some embodiments, a non-naturally occurring microbial organism of the invention is generated from a host that contains the enzymatic capability to synthesize fatty alcohol, fatty aldehyde or fatty acid. In this specific embodiment it can be useful to increase the synthesis or accumulation of a fatty alcohol, fatty aldehyde or fatty acid pathway product to, for example, drive fatty alcohol, fatty aldehyde or fatty acid pathway reactions toward fatty alcohol, fatty aldehyde or fatty acid production. Increased synthesis or accumulation can be accomplished by, for example, overexpression of nucleic acids encoding one or more of the above-described fatty alcohol, fatty aldehyde or fatty acid pathway enzymes or proteins. Overexpression of the enzyme or enzymes and/or protein or proteins of the fatty alcohol, fatty aldehyde or fatty acid pathway can occur, for example, through exogenous expression of the endogenous gene or genes, or through exogenous expression of the heterologous gene or genes. Therefore, naturally occurring organisms can be readily generated to be non-naturally occurring microbial organisms of the invention, for example, producing fatty alcohol, fatty aldehyde or fatty acid, through overexpression of one, two, three, four, five, six, seven, or eight, that is, up to all nucleic acids encoding fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway enzymes or proteins. In addition, a non-naturally occurring organism can be generated by mutagenesis of an endogenous gene that results in an increase in activity of an enzyme in the fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway.

In particularly useful embodiments, exogenous expression of the encoding nucleic acids is employed. Exogenous expression confers the ability to custom tailor the expression and/or regulatory elements to the host and application to achieve a desired expression level that is controlled by the user. However, endogenous expression also can be utilized in other embodiments such as by removing a negative regulatory effector or induction of the gene's promoter when linked to an inducible promoter or other regulatory element. Thus, an endogenous gene having a naturally occurring inducible promoter can be up-regulated by providing the appropriate inducing agent, or the regulatory region of an endogenous gene can be engineered to incorporate an inducible regulatory element, thereby allowing the regulation of increased expression of an endogenous gene at a desired time. Similarly, an inducible promoter can be included as a regulatory element for an exogenous gene introduced into a non-naturally occurring microbial organism.

It is understood that, in methods of the invention, any of the one or more exogenous nucleic acids can be introduced into a microbial organism to produce a non-naturally occurring microbial organism of the invention. The nucleic acids can be introduced so as to confer, for example, a fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway onto the microbial organism. Alternatively, encoding nucleic acids can be introduced to produce an intermediate microbial organism having the biosynthetic capability to catalyze some of the required reactions to confer fatty alcohol, fatty aldehyde or fatty acid biosynthetic capability. For example, a non-naturally occurring microbial organism having a fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway can comprise at least two exogenous nucleic acids encoding desired enzymes or proteins, such as the combination of a thiolase and an acyl-CoA reductase (alcohol forming), or alternatively a 2-oxoacyl-CoA reductase and an acyl-CoA hydrolase, or alternatively a enoyl-CoA reductase and an acyl-CoA reductase (aldehyde forming), and the like. Thus, it is understood that any combination of two or more enzymes or proteins of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention. Similarly, it is understood that any combination of three or more enzymes or proteins of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention, for example, a thiolase, an enoyl-CoA reductase and a aldehyde dehydrogenase (acid forming), or alternatively a 3-hydroxyacyl-coA dehydratase, an acyl-CoA:ACP acyltransferase and a thioesterase, or alternatively a 3-oxoacyl-CoA reductase, an acyl-CoA hydrolase and a carboxylic acid reductase, and so forth, as desired, so long as the combination of enzymes and/or proteins of the desired biosynthetic pathway results in production of the corresponding desired product. Similarly, any combination of four, five, six, seven, eight or more enzymes or proteins of a biosynthetic pathway as disclosed herein can be included in a non-naturally occurring microbial organism of the invention, as desired, so long as the combination of enzymes and/or proteins of the desired biosynthetic pathway results in production of the corresponding desired product.

In addition to the biosynthesis of fatty alcohol, fatty aldehyde or fatty acid as described herein, the non-naturally occurring microbial organisms and methods of the invention also can be utilized in various combinations with each other and/or with other microbial organisms and methods well known in the art to achieve product biosynthesis by other routes. For example, one alternative to produce fatty alcohol, fatty aldehyde or fatty acid other than use of the fatty alcohol, fatty aldehyde or fatty acid producers is through addition of another microbial organism capable of converting a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate to fatty alcohol, fatty aldehyde or fatty acid. One such procedure includes, for example, the fermentation of a microbial organism that produces a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate. The fatty alcohol, fatty aldehyde or fatty acid pathway intermediate can then be used as a substrate for a second microbial organism that converts the fatty alcohol, fatty aldehyde or fatty acid pathway intermediate to fatty alcohol, fatty aldehyde or fatty acid. The fatty alcohol, fatty aldehyde or fatty acid pathway intermediate can be added directly to another culture of the second organism or the original culture of the fatty alcohol, fatty aldehyde or fatty acid pathway intermediate producers can be depleted of these microbial organisms by, for example, cell separation, and then subsequent addition of the second organism to the fermentation broth can be utilized to produce the final product without intermediate purification steps.

In other embodiments, the non-naturally occurring microbial organisms and methods of the invention can be assembled in a wide variety of subpathways to achieve biosynthesis of, for example, fatty alcohol, fatty aldehyde or fatty acid. In these embodiments, biosynthetic pathways for a desired product of the invention can be segregated into different microbial organisms, and the different microbial organisms can be co-cultured to produce the final product. In such a biosynthetic scheme, the product of one microbial organism is the substrate for a second microbial organism until the final product is synthesized. For example, the biosynthesis of fatty alcohol, fatty aldehyde or fatty acid can be accomplished by constructing a microbial organism that contains biosynthetic pathways for conversion of one pathway intermediate to another pathway intermediate or the product. Alternatively, fatty alcohol, fatty aldehyde or fatty acid also can be biosynthetically produced from microbial organisms through co-culture or co-fermentation using two organisms in the same vessel, where the first microbial organism produces a fatty alcohol, fatty aldehyde or fatty acid intermediate and the second microbial organism converts the intermediate to fatty alcohol, fatty aldehyde or fatty acid.

Given the teachings and guidance provided herein, those skilled in the art will understand that a wide variety of combinations and permutations exist for the non-naturally occurring microbial organisms and methods of the invention together with other microbial organisms, with the co-culture of other non-naturally occurring microbial organisms having subpathways and with combinations of other chemical and/or biochemical procedures well known in the art to produce fatty alcohol, fatty aldehyde or fatty acid.

Similarly, it is understood by those skilled in the art that a host organism can be selected based on desired characteristics for introduction of one or more gene disruptions to increase production of fatty alcohol, fatty aldehyde or fatty acid. Thus, it is understood that, if a genetic modification is to be introduced into a host organism to disrupt a gene, any homologs, orthologs or paralogs that catalyze similar, yet non-identical metabolic reactions can similarly be disrupted to ensure that a desired metabolic reaction is sufficiently disrupted. Because certain differences exist among metabolic networks between different organisms, those skilled in the art will understand that the actual genes disrupted in a given organism may differ between organisms. However, given the teachings and guidance provided herein, those skilled in the art also will understand that the methods of the invention can be applied to any suitable host microorganism to identify the cognate metabolic alterations needed to construct an organism in a species of interest that will increase fatty alcohol, fatty aldehyde or fatty acid biosynthesis. In a particular embodiment, the increased production couples biosynthesis of fatty alcohol, fatty aldehyde or fatty acid to growth of the organism, and can obligatorily couple production of fatty alcohol, fatty aldehyde or fatty acid to growth of the organism if desired and as disclosed herein.

Sources of encoding nucleic acids for a fatty alcohol, fatty aldehyde or fatty acid pathway enzyme or protein can include, for example, any species where the encoded gene product is capable of catalyzing the referenced reaction. Such species include both prokaryotic and eukaryotic organisms including, but not limited to, bacteria, including archaea and eubacteria, and eukaryotes, including yeast, plant, insect, animal, and mammal, including human. Exemplary species for such sources include, for example, Escherichia coli, 255956237 Penicillium chrysogenum Wisconsin 54-1255, Acetobacter pasteurians, Acidaminococcus fermentans, Acinetobacter bayliyi, Acinetobacter calcoaceticus, Acinetobacter sp. ADP1, Acinetobacter sp. Strain M-1, Actinobacillus succinogenes, Aedes aegypti, Agrobacterium tumefaciens, Alkaliphilus metalliredigens QYMF, Alkaliphilus oremlandii OhILAs, Anabaena variabilis ATCC 29413, Anaerobiospirillum succiniciproducens, Anopheles gambiae str. PEST, Apis mellifera, Aquifex aeolicus, Arabidopsis thaliana, Archaeoglobus fulgidus, Archaeoglobus fulgidus DSM 4304, Ascaris suum, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus niger CBS 513.88, Aspergillus terreus NIH2624, Azotobacter vinelandii DJ, Bacillus cereus, Bacillus megaterium, Bacillus methanolicus MGA3, Bacillus methanolicus PB1, Bacillus sp. SG-1, Bacillus subtilis, Bacillus weihenstephanensis KBAB4, Bacteroides fragilis, Bombyx mori, Bos taurus, Bradyrhizobium japonicum, Bradyrhizobium japonicum USDA110, Brassica napsus, Burkholderia ambifaria AMMD, Burkholderia multivorans ATCC 17616, Burkholderia phymatum, Burkholderia stabilis, butyrate producing bacterium L2-50, Caenorhabditis briggsae AF16, Caenorhabditis elegans, Campylobacter jejuni, Candida albicans, Candida boidinii, Candida methylica, Candida parapsilosis, Candida tropicalis, Candida tropicalis MYA-3404, Candidatus Protochlamydia amoebophila, Canis lupus familiaris (dog), Carboxydothermus hydrogenoformans, Carthamus tinctorius, Chlamydomonas reinhardtii, Chlorobium limicola, Chlorobium tepidum, Chloroflexus aurantiacus, Citrus junos, Clostridium acetobutylicum, Clostridium aminobutyricum, Clostridium beijerinckii, Clostridium beijerinckii NCIMB 8052, Clostridium carboxidivorans P7, Clostridium kluyveri, Clostridium kluyveri DSM 555, Clostridium pasteurianum, Clostridium saccharoperbutylacetonicum, Clostridium symbiosum, Clostridium tetani E88, Colwellia psychrerythraea 34H, Corynebacterium glutamicum, Cryptococcus neoformans var, Cryptosporidium parvum Iowa II, Cuphea hookeriana, Cuphea palustris, Cupriavidus necator, Cupriavidus taiwanensis, Cyanobium PCC7001, Cyanothece sp. PCC 7425, Danio rerio, Desulfatibacillum alkenivorans AK-01, Desulfococcus oleovorans Hxd3, Desulfovibrio africanus, Dictyostelium discoideum, Dictyostelium discoideum AX4, Drosophila melanogaster, Erythrobacter sp. NAP1, Escherichia coli K-12 MG1655, Euglena gracilis, Flavobacteria bacterium BAL38, Fusobacterium nucleatum, Geobacillus thermodenitrificans, Haemophilus influenza, Haloarcula marismortui, Haloarcula marismortui ATCC 43049, Halomonas sp. HTNK1, Helianthus annuus, Helicobacter pylori, Helicobacter pylori 26695, Homo sapiens, Hydrogenobacter thermophilus, Klebsiella pneumoniae, Kluyveromyces lactis, Kluyveromyces lactis NRRL Y-1140, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus reuteri, Lactococcus lactis, Leifsonia sp. S749, Leuconostoc mesenteroides, Lyngbya sp. PCC 8106, Macaca mulatta, Magnetospirillum magneticum AMB-1, Mannheimia succiniciproducens, marine gamma proteobacterium HTCC2080, Marinobacter aquaeolei, Marinobacter aquaeolei VT8, Megathyrsus maximus, Mesorhizobium loti, Metallosphaera sedula, Methanosarcina thermophile, Methanothermobacter thermautotrophicus, Methylobacterium extorquens, Monosiga brevicollis MX1, Moorella thermoacetica, Moorella thermoacetica ATCC 39073, Mus musculus, Mycobacterium avium subsp. paratuberculosis K-10, Mycobacterium bovis BCG, Mycobacterium marinum M, Mycobacterium smegmatis, Mycobacterium smegmatis MC2 155, Mycobacterium sp. (strain JLS), Mycobacterium sp. MCS, Mycobacterium sp. strain JLS, Mycobacterium tuberculosis, Myxococcus xanthus DK 1622, Nematostella vectensis, Neurospora crassa OR74A, Nicotiana tabacum, Nocardia brasiliensis, Nocardia farcinica IFM 10152, Nocardia iowensis, Nodularia spumigena CCY9414, Nostoc azollae, Nostoc sp. PCC 7120, Opitutaceae bacterium TAV2, Paracoccus denitriflcans, Penicillium chrysogenum, Perkinsus marinus ATCC 50983, Photobacterium phosphoreum, Photobacterium sp. SKA34, Picea sitchensis, Pichia pastoris, Pichia pastoris GS115, Plasmodium falciparum, Porphyromonas gingivalis, Porphyromonas gingivalis W83, Prochlorococcus marinus MIT 9312, Propionigenium modestum, Pseudomonas aeruginosa, Pseudomonas aeruginosa PAO1, Pseudomonas fluorescens, Pseudomonas fluorescens Pf0-1, Pseudomonas knackmussii, Pseudomonas knackmussii (B13), Pseudomonas putida, Pseudomonas putida GB-1, Pseudomonas sp, Pseudomonas sp. CF600, Pseudomonas stutzeri, Pseudomonas stutzeri A1501, Pseudomonas syringae, Pyrobaculum aerophilum str. IM2, Ralstonia eutropha, Ralstonia metallidurans, Rattus norvegicus, Reinekea sp. MED297, Rhizobium etli CFN 42, Rhizobium leguminosarum, Rhodobacter sphaeroides, Rhodococcus erythropolis, Rhodococcus sp., Rhodopseudomonas palustris, Roseiflexus castenholzii, Roseovarius sp. HTCC2601, Saccharomyces cerevisiae, Saccharomyces cerevisiae s288c, Salmonella enteric, Salmonella enterica subsp. enterica serovar Typhimurium str. LT2, Salmonella typhimurium, Salmonella typhimurium LT2, Scheffersomyces stipitis, Schizosaccharomyces pombe, Shigella dysenteriae, Shigella sonnei, Simmondsia chinensis, Solanum lycopersicum, Sordaria macrospora, Staphylococcus aureus, Stenotrophomonas maltophilia, Streptococcus mutans, Streptococcus pneumoniae, Streptococcus sanguinis, Streptomyces anulatus, Streptomyces avermitillis, Streptomyces cinnamonensis, Streptomyces coelicolor, Streptomyces griseus subsp. griseus NBRC 13350, Streptomyces luridus, Streptomyces sp CL190, Streptomyces sp. KO-3988, Streptomyces viridochromogenes, Streptomyces wedmorensis, Strongylocentrotus purpuratus, Sulfolobus acidocaldarius, Sulfolobus solfataricus, Sulfolobus tokodaii, Sulfurihydrogenibium subterraneum, Sulfurimonas denitrificans, Sus scrofa, Synechococcus elongatus PCC 6301, Synechococcus elongatus PCC 7942, Synechococcus sp. PCC 7002, Syntrophobacter fumaroxidans, Syntrophus aciditrophicus, Tetraodon nigroviridis, Thermoanaerobacter ethanolicus JW 200, Thermoanaerobacter pseudethanolicus ATCC 33223, Thermococcus litoralis, Thermoproteus neutrophilus, Thermotoga maritime, Treponema denticola, Tribolium castaneum, Trichomonas vaginalis G3, Triticum aestivum, Trypanosoma brucei, Trypanosoma cruzi strain CL Brener, Tsukamurella paurometabola DSM 20162, Umbellularia California, Veillonella parvula, Vibrio cholerae V51, Xenopus tropicalis, Yarrowia lipolytica, Zea mays, Zoogloea ramiger, Zymomonas mobilis, Zymomonas mobilis subsp. mobilis ZM4, as well as other exemplary species disclosed herein or available as source organisms for corresponding genes. However, with the complete genome sequence available for now more than 550 species (with more than half of these available on public databases such as the NCBI), including 395 microorganism genomes and a variety of yeast, fungi, plant, and mammalian genomes, the identification of genes encoding the requisite fatty alcohol, fatty aldehyde or fatty acid biosynthetic activity for one or more genes in related or distant species, including for example, homologues, orthologs, paralogs and nonorthologous gene displacements of known genes, and the interchange of genetic alterations between organisms is routine and well known in the art. Accordingly, the metabolic alterations allowing biosynthesis of fatty alcohol, fatty aldehyde or fatty acid described herein with reference to a particular organism such as E. coli can be readily applied to other microorganisms, including prokaryotic and eukaryotic organisms alike. Given the teachings and guidance provided herein, those skilled in the art will know that a metabolic alteration exemplified in one organism can be applied equally to other organisms.

In some instances, such as when an alternative fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway exists in an unrelated species, fatty alcohol, fatty aldehyde or fatty acid biosynthesis can be conferred onto the host species by, for example, exogenous expression of a paralog or paralogs from the unrelated species that catalyzes a similar, yet non-identical metabolic reaction to replace the referenced reaction. Because certain differences among metabolic networks exist between different organisms, those skilled in the art will understand that the actual gene usage between different organisms may differ. However, given the teachings and guidance provided herein, those skilled in the art also will understand that the teachings and methods of the invention can be applied to all microbial organisms using the cognate metabolic alterations to those exemplified herein to construct a microbial organism in a species of interest that will synthesize fatty alcohol, fatty aldehyde or fatty acid.

Methods for constructing and testing the expression levels of a non-naturally occurring fatty alcohol, fatty aldehyde or fatty acid-producing host can be performed, for example, by recombinant and detection methods well known in the art. Such methods can be found described in, for example, Sambrook et al., Molecular Cloning: A Laboratory Manual, Third Ed., Cold Spring Harbor Laboratory, New York (2001); and Ausubel et al., Current Protocols in Molecular Biology, John Wiley and Sons, Baltimore, Md. (1999).

Exogenous nucleic acid sequences involved in a pathway for production of fatty alcohol, fatty aldehyde or fatty acid can be introduced stably or transiently into a host cell using techniques well known in the art including, but not limited to, conjugation, electroporation, chemical transformation, transduction, transfection, and ultrasound transformation. For exogenous expression in E. coli or other prokaryotic cells, some nucleic acid sequences in the genes or cDNAs of eukaryotic nucleic acids can encode targeting signals such as an N-terminal mitochondrial or other targeting signal, which can be removed before transformation into prokaryotic host cells, if desired. For example, removal of a mitochondrial leader sequence led to increased expression in E. coli (Hoffmeister et al., J. Biol. Chem. 280:4329-4338 (2005)). For exogenous expression in yeast or other eukaryotic cells, genes can be expressed in the cytosol without the addition of leader sequence, or can be targeted to mitochondrion or other organelles, or targeted for secretion, by the addition of a suitable targeting sequence such as a mitochondrial targeting or secretion signal suitable for the host cells. Thus, it is understood that appropriate modifications to a nucleic acid sequence to remove or include a targeting sequence can be incorporated into an exogenous nucleic acid sequence to impart desirable properties. Furthermore, genes can be subjected to codon optimization with techniques well known in the art to achieve optimized expression of the proteins.

An expression vector or vectors can be constructed to include one or more fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathway encoding nucleic acids as exemplified herein operably linked to expression control sequences functional in the host organism. Expression vectors applicable for use in the microbial host organisms of the invention include, for example, plasmids, phage vectors, viral vectors, episomes and artificial chromosomes, including vectors and selection sequences or markers operable for stable integration into a host chromosome. Additionally, the expression vectors can include one or more selectable marker genes and appropriate expression control sequences. Selectable marker genes also can be included that, for example, provide resistance to antibiotics or toxins, complement auxotrophic deficiencies, or supply critical nutrients not in the culture media. Expression control sequences can include constitutive and inducible promoters, transcription enhancers, transcription terminators, and the like which are well known in the art. When two or more exogenous encoding nucleic acids are to be co-expressed, both nucleic acids can be inserted, for example, into a single expression vector or in separate expression vectors. For single vector expression, the encoding nucleic acids can be operationally linked to one common expression control sequence or linked to different expression control sequences, such as one inducible promoter and one constitutive promoter. The transformation of exogenous nucleic acid sequences involved in a metabolic or synthetic pathway can be confirmed using methods well known in the art. Such methods include, for example, nucleic acid analysis such as Northern blots or polymerase chain reaction (PCR) amplification of mRNA, or immunoblotting for expression of gene products, or other suitable analytical methods to test the expression of an introduced nucleic acid sequence or its corresponding gene product. It is understood by those skilled in the art that the exogenous nucleic acid is expressed in a sufficient amount to produce the desired product, and it is further understood that expression levels can be optimized to obtain sufficient expression using methods well known in the art and as disclosed herein.

In some embodiments, the invention provides a method for producing a compound of Formula (I):

wherein R₁ is C₁₋₂₄ linear alkyl; R₂ is CH₂OH, CHO, or COOH; R₃ is H, OH, or oxo (═O); and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four, comprising culturing a non-naturally occurring microbial organism of under conditions and for a sufficient period of time to produce the compound of Formula (I), wherein the non-naturally occurring microbial organism has a MI-FAE cycle and a termination pathway, wherein the MI-FAE cycle includes one or more thiolase, one or more 3-oxoacyl-CoA reductase, one or more 3-hydroxyacyl-CoA dehydratase, and one or more enoyl-CoA reductase, wherein the termination pathway includes a pathway shown in FIG. 1, 6 or 7 selected from: (1) 1H; (2) 1K and 1L; (3) 1E and 1N; (4) 1K, 1J, and 1N; (5) 1E; (6) 1K and 1J; (7) 1H and 1N; (8) 1K, 1L, and 1N; (9) 1E and 1F; (10) 1K, 1J, and 1F; (11) 1H, 1N, and 1F; (12) 1K, 1L, 1N, and 1F; and (13) 1G, wherein 1E is an acyl-CoA reductase (aldehyde forming), wherein 1F is an alcohol dehydrogenase, wherein 1G is an acyl-CoA reductase (alcohol forming), wherein 1H is an acyl-CoA hydrolase, acyl-CoA transferase or acyl-CoA synthase, wherein 1J is an acyl-ACP reductase, wherein 1K is an acyl-CoA:ACP acyltransferase, wherein 1L is a thioesterase, wherein 1N is an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce the compound of Formula (I), wherein the substrate of each of said enzymes of the MI-FAE cycle and the termination pathway are independently selected from a compound of Formula (II), propionyl-CoA or acetyl-CoA:

wherein R₁ is C₁₋₂₄ linear alkyl; R₃ is H, OH, or oxo (═O); R₄ is S—CoA, ACP, OH or H; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; wherein said one or more enzymes of the MI-FAE cycle are each selective for a compound of Formula (II) having a number of carbon atoms at R₁ that is no greater than the number of carbon atoms at R₁ of said compound of Formula (I), and wherein said one or more enzymes of the termination pathway are each selective for a compound of Formula (II) having a number of carbon atoms at R₁ that is no less than the number of carbon atoms at R₁ of said compound of Formula (I).

In some embodiments, the invention provides a method for producing a compound of Formula (I) wherein R₁ is C₁₋₁₇ linear alkyl. In another aspect of the invention, the R₁ of the compound of Formula (I) is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₋₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some aspects of the invention, the microbial organism microbial organism used in the method of the invention includes two, three, or four exogenous nucleic acids each encoding an enzyme of the MI-FAE cycle. In some aspects of the invention, the microbial organism used in the method of the invention includes two, three, or four exogenous nucleic acids each encoding an enzyme of the termination pathway. In some aspects of the invention, the microbial organism used in the method of the invention includes exogenous nucleic acids encoding each of the enzymes of at least one of the pathways selected from (1)-(13). In some aspects, the at least one exogenous nucleic acid is a heterologous nucleic acid. In some aspects, the non-naturally occurring microbial organism used in the method of the invention is in a substantially anaerobic culture medium.

In some embodiments, the invention provides a method for producing a fatty alcohol selected from the Formulas (III)-(VI):

wherein R₁ is C₁₋₂₄ linear alkyl, or alternatively R₁ is C₁₋₁₇ linear alkyl, or alternatively R₁ is C₉₋₁₃ linear alkyl. In some aspects of the invention, R₁ is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some embodiments, the invention provides a method for producing a fatty aldehyde selected from the Formulas (VII)-(X):

wherein R₁ is C₁₋₂₄ linear alkyl, or alternatively R₁ is C₁₋₁₇ linear alkyl, or alternatively R₁ is C₉₋₁₃ linear alkyl. In some aspects of the invention, R₁ is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some embodiments, the invention provides a method for producing a fatty acid selected from the Formulas (XI)-(XIV):

wherein R₁ is C₁₋₂₄ linear alkyl, or alternatively R₁ is C₁₋₁₇ linear alkyl, or alternatively R₁ is C₉₋₁₃ linear alkyl. In some aspects of the invention, R₁ is C₁ linear alkyl, C₂ linear alkyl, C₃ linear alkyl, C₄ linear alkyl, C₅ linear alkyl, C₆ linear alkyl, C₇ linear alkyl, C₈ linear alkyl, C₉ linear alkyl, C₁₀ linear alkyl, C₁₁, linear alkyl, C₁₂ linear alkyl or C₁₃ linear alkyl, C₁₄ linear alkyl, C₁₅ linear alkyl, C₁₆ linear alkyl, C₁₇ linear alkyl, C₁₈ linear alkyl, C₁₉ linear alkyl, C₂₀ linear alkyl, C₂₁ linear alkyl, C₂₂ linear alkyl, C₂₃ linear alkyl, or C₂₄ linear alkyl.

In some embodiments, the method for producing a fatty alcohol, fatty aldehyde or fatty acid described herein includes using a non-naturally occurring microbial organism that has an acetyl-CoA pathway and at least one exogenous nucleic acid encoding an acetyl-CoA pathway enzyme expressed in a sufficient amount to produce acetyl-CoA, wherein the acetyl-CoA pathway includes a pathway shown in FIG. 2, 3, 4 or 5 selected from: (1) 2A and 2B; (2) 2A, 2C, and 2D; (3) 2H; (4) 2G and 2D; (5) 2E, 2F and 2B; (6) 2E and 2I; (7) 2J, 2F and 2B; (8) 2J and 2I; (9) 3A, 3B, and 3C; (10) 3A, 3B, 3J, 3K, and 3D; (11) 3A, 3B, 3G, and 3D; (12) 3A, 3F, and 3D; (13) 3N, 3H, 3B and 3C; (14) 3N, 3H, 3B, 3J, 3K, and 3D; (15) 3N, 3H, 3B, 3G, and 3D; (16) 3N, 3H, 3F, and 3D; (17) 3L, 3M, 3B and 3C; (18) 3L, 3M, 3B, 3J, 3K, and 3D; (19) 3L, 3M, 3B, 3G, and 3D; (20) 3L, 3M, 3F, and 3D; (21) 4A, 4B, 4D, 4H, 4I, and 4J; (22) 4A, 4B, 4E, 4F, 4H, 4I, and 4J; (23) 4A, 4B, 4E, 4K, 4L, 4H, 4I, and 4J; (24) 4A, 4C, 4D, 4H, and 4J; (25) 4A, 4C, 4E, 4F, 4H, and 4J; (26) 4A, 4C, 4E, 4K, 4L, 4H, and 4J; (27) 5A, 5B, 5D, and 5G; (28) 5A, 5B, 5E, 5F, and 5G; (29) 5A, 5B, 5E, 5K, 5L, and 5G; (30) 5A, 5C, and 5D; (31) 5A, 5C, 5E, and 5F; and (32) 5A, 5C, 5E, 5K, and 5L, wherein 2A is a pyruvate oxidase (acetate-forming), wherein 2B is an acetyl-CoA synthetase, an acetyl-CoA ligase or an acetyl-CoA transferase, wherein 2C is an acetate kinase, wherein 2D is a phosphotransacetylase, wherein 2E is a pyruvate decarboxylase, wherein 2F is an acetaldehyde dehydrogenase, wherein 2G is a pyruvate oxidase (acetyl-phosphate forming), wherein 2H is a pyruvate dehydrogenase, a pyruvate:ferredoxin oxidoreductase, a pyruvate:NAD(P)H oxidoreductase or a pyruvate formate lyase, wherein 2I is an acetaldehyde dehydrogenase (acylating), wherein 2J is a threonine aldolase, wherein 3A is a phosphoenolpyruvate (PEP) carboxylase or a PEP carboxykinase, wherein 3B is an oxaloacetate decarboxylase, wherein 3C is a malonate semialdehyde dehydrogenase (acetylating), wherein 3D is an acetyl-CoA carboxylase or a malonyl-CoA decarboxylase, wherein 3F is an oxaloacetate dehydrogenase or an oxaloacetate oxidoreductase, wherein 3G is a malonate semialdehyde dehydrogenase (acylating), wherein 3H is a pyruvate carboxylase, wherein 3J is a malonate semialdehyde dehydrogenase, wherein 3K is a malonyl-CoA synthetase or a malonyl-CoA transferase, wherein 3L is a malic enzyme, wherein 3M is a malate dehydrogenase or a malate oxidoreductase, wherein 3N is a pyruvate kinase or a PEP phosphatase, wherein 4A is a citrate synthase, wherein 4B is a citrate transporter, wherein 4C is a citrate/malate transporter, wherein 4D is an ATP citrate lyase, wherein 4E is a citrate lyase, wherein 4F is an acetyl-CoA synthetase or an acetyl-CoA transferase, wherein 4H is a cytosolic malate dehydrogenase, wherein 4I is a malate transporter, wherein 4J is a mitochondrial malate dehydrogenase, wherein 4K is an acetate kinase, wherein 4L is a phosphotransacetylase, wherein 5A is a citrate synthase, wherein 5B is a citrate transporter, wherein 5C is a citrate/oxaloacetate transporter, wherein 5D is an ATP citrate lyase, wherein 5E is a citrate lyase, wherein 5F is an acetyl-CoA synthetase or an acetyl-CoA transferase, wherein 5G is an oxaloacetate transporter, wherein 5K is an acetate kinase, and wherein 5L is a phosphotransacetylase.

In some aspects, the microbial organism used in the method of the invention includes two, three, four, five, six, seven or eight exogenous nucleic acids each encoding an acetyl-CoA pathway enzyme. In some aspects, the microbial organism used in the method of the invention includes exogenous nucleic acids encoding each of the acetyl-CoA pathway enzymes of at least one of the pathways selected from (1)-(32).

Suitable purification and/or assays to test for the production of fatty alcohol, fatty aldehyde or fatty acid can be performed using well known methods. Suitable replicates such as triplicate cultures can be grown for each engineered strain to be tested. For example, product and byproduct formation in the engineered production host can be monitored. The final product and intermediates, and other organic compounds, can be analyzed by methods such as HPLC (High Performance Liquid Chromatography), GC-MS (Gas Chromatography-Mass Spectroscopy) and LC-MS (Liquid Chromatography-Mass Spectroscopy) or other suitable analytical methods using routine procedures well known in the art. The release of product in the fermentation broth can also be tested with the culture supernatant. Byproducts and residual glucose can be quantified by HPLC using, for example, a refractive index detector for glucose and alcohols, and a UV detector for organic acids (Lin et al., Biotechnol. Bioeng. 90:775-779 (2005)), or other suitable assay and detection methods well known in the art. The individual enzyme or protein activities from the exogenous DNA sequences can also be assayed using methods well known in the art.

The fatty alcohol, fatty aldehyde or fatty acid can be separated from other components in the culture using a variety of methods well known in the art. Such separation methods include, for example, extraction procedures as well as methods that include continuous liquid-liquid extraction, pervaporation, membrane filtration, membrane separation, reverse osmosis, electrodialysis, distillation, crystallization, centrifugation, extractive filtration, ion exchange chromatography, size exclusion chromatography, adsorption chromatography, and ultrafiltration. All of the above methods are well known in the art.

Any of the non-naturally occurring microbial organisms described herein can be cultured to produce and/or secrete the biosynthetic products of the invention. For example, the fatty alcohol, fatty aldehyde or fatty acid producers can be cultured for the biosynthetic production of fatty alcohol, fatty aldehyde or fatty acid.

For the production of fatty alcohol, fatty aldehyde or fatty acid, the recombinant strains are cultured in a medium with carbon source and other essential nutrients. It is sometimes desirable and can be highly desirable to maintain anaerobic conditions in the fermenter to reduce the cost of the overall process. Such conditions can be obtained, for example, by first sparging the medium with nitrogen and then sealing the flasks with a septum and crimp-cap. For strains where growth is not observed anaerobically, microaerobic or substantially anaerobic conditions can be applied by perforating the septum with a small hole for limited aeration. Exemplary anaerobic conditions have been described previously and are well-known in the art. Exemplary aerobic and anaerobic conditions are described, for example, in United State publication 2009/0047719, filed Aug. 10, 2007. Fermentations can be performed in a batch, fed-batch or continuous manner, as disclosed herein. Fermentations can also be conducted in two phases, if desired. The first phase can be aerobic to allow for high growth and therefore high productivity, followed by an anaerobic phase of high fatty alcohol, fatty aldehyde or fatty acid yields.

If desired, the pH of the medium can be maintained at a desired pH, in particular neutral pH, such as a pH of around 7 by addition of a base, such as NaOH or other bases, or acid, as needed to maintain the culture medium at a desirable pH. The growth rate can be determined by measuring optical density using a spectrophotometer (600 nm), and the glucose uptake rate by monitoring carbon source depletion over time.

The growth medium can include, for example, any carbohydrate source which can supply a source of carbon to the non-naturally occurring microorganism. Such sources include, for example, sugars such as glucose, xylose, arabinose, galactose, mannose, fructose, sucrose and starch. Other sources of carbohydrate include, for example, renewable feedstocks and biomass. Exemplary types of biomasses that can be used as feedstocks in the methods of the invention include cellulosic biomass, hemicellulosic biomass and lignin feedstocks or portions of feedstocks. Such biomass feedstocks contain, for example, carbohydrate substrates useful as carbon sources such as glucose, xylose, arabinose, galactose, mannose, fructose and starch. Given the teachings and guidance provided herein, those skilled in the art will understand that renewable feedstocks and biomass other than those exemplified above also can be used for culturing the microbial organisms of the invention for the production of fatty alcohol, fatty aldehyde or fatty acid.

In addition to renewable feedstocks such as those exemplified above, the fatty alcohol, fatty aldehyde or fatty acid microbial organisms of the invention also can be modified for growth on syngas as its source of carbon. In this specific embodiment, one or more proteins or enzymes are expressed in the fatty alcohol, fatty aldehyde or fatty acid producing organisms to provide a metabolic pathway for utilization of syngas or other gaseous carbon source.

Synthesis gas, also known as syngas or producer gas, is the major product of gasification of coal and of carbonaceous materials such as biomass materials, including agricultural crops and residues. Syngas is a mixture primarily of H₂ and CO and can be obtained from the gasification of any organic feedstock, including but not limited to coal, coal oil, natural gas, biomass, and waste organic matter. Gasification is generally carried out under a high fuel to oxygen ratio. Although largely H₂ and CO, syngas can also include CO₂ and other gases in smaller quantities. Thus, synthesis gas provides a cost effective source of gaseous carbon such as CO and, additionally, CO₂.

The Wood-Ljungdahl pathway catalyzes the conversion of CO and H₂ to acetyl-CoA and other products such as acetate. Organisms capable of utilizing CO and syngas also generally have the capability of utilizing CO₂ and CO₂/H₂ mixtures through the same basic set of enzymes and transformations encompassed by the Wood-Ljungdahl pathway. H₂-dependent conversion of CO₂ to acetate by microorganisms was recognized long before it was revealed that CO also could be used by the same organisms and that the same pathways were involved. Many acetogens have been shown to grow in the presence of CO₂ and produce compounds such as acetate as long as hydrogen is present to supply the necessary reducing equivalents (see for example, Drake, Acetogenesis, pp. 3-60 Chapman and Hall, New York, (1994)). This can be summarized by the following equation: 2CO₂+4H₂ +nADP+nPi→CH₃COOH+2H₂O+nATP

Hence, non-naturally occurring microorganisms possessing the Wood-Ljungdahl pathway can utilize CO₂ and H₂ mixtures as well for the production of acetyl-CoA and other desired products.

The Wood-Ljungdahl pathway is well known in the art and consists of 12 reactions which can be separated into two branches: (1) methyl branch and (2) carbonyl branch. The methyl branch converts syngas to methyl-tetrahydrofolate (methyl-THF) whereas the carbonyl branch converts methyl-THF to acetyl-CoA. The reactions in the methyl branch are catalyzed in order by the following enzymes or proteins: ferredoxin oxidoreductase, formate dehydrogenase, formyltetrahydrofolate synthetase, methenyltetrahydrofolate cyclodehydratase, methylenetetrahydrofolate dehydrogenase and methylenetetrahydrofolate reductase. The reactions in the carbonyl branch are catalyzed in order by the following enzymes or proteins: methyltetrahydrofolate:corrinoid protein methyltransferase (for example, AcsE), corrinoid iron-sulfur protein, nickel-protein assembly protein (for example, AcsF), ferredoxin, acetyl-CoA synthase, carbon monoxide dehydrogenase and nickel-protein assembly protein (for example, CooC). Following the teachings and guidance provided herein for introducing a sufficient number of encoding nucleic acids to generate a fatty alcohol, fatty aldehyde or fatty acid pathway, those skilled in the art will understand that the same engineering design also can be performed with respect to introducing at least the nucleic acids encoding the Wood-Ljungdahl enzymes or proteins absent in the host organism. Therefore, introduction of one or more encoding nucleic acids into the microbial organisms of the invention such that the modified organism contains the complete Wood-Ljungdahl pathway will confer syngas utilization ability.

Additionally, the reductive (reverse) tricarboxylic acid cycle coupled with carbon monoxide dehydrogenase and/or hydrogenase activities can also be used for the conversion of CO, CO₂ and/or H₂ to acetyl-CoA and other products such as acetate. Organisms capable of fixing carbon via the reductive TCA pathway can utilize one or more of the following enzymes: ATP citrate-lyase, citrate lyase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate:ferredoxin oxidoreductase, succinyl-CoA synthetase, succinyl-CoA transferase, fumarate reductase, fumarase, malate dehydrogenase, NAD(P)H:ferredoxin oxidoreductase, carbon monoxide dehydrogenase, and hydrogenase. Specifically, the reducing equivalents extracted from CO and/or H₂ by carbon monoxide dehydrogenase and hydrogenase are utilized to fix CO₂ via the reductive TCA cycle into acetyl-CoA or acetate. Acetate can be converted to acetyl-CoA by enzymes such as acetyl-CoA transferase, acetate kinase/phosphotransacetylase, and acetyl-CoA synthetase. Acetyl-CoA can be converted to the fatty alcohol, fatty aldehyde or fatty acid precursors, glyceraldehyde-3-phosphate, phosphoenolpyruvate, and pyruvate, by pyruvate:ferredoxin oxidoreductase and the enzymes of gluconeogenesis. Following the teachings and guidance provided herein for introducing a sufficient number of encoding nucleic acids to generate a fatty alcohol, fatty aldehyde or fatty acid pathway, those skilled in the art will understand that the same engineering design also can be performed with respect to introducing at least the nucleic acids encoding the reductive TCA pathway enzymes or proteins absent in the host organism. Therefore, introduction of one or more encoding nucleic acids into the microbial organisms of the invention such that the modified organism contains a reductive TCA pathway can confer syngas utilization ability.

Accordingly, given the teachings and guidance provided herein, those skilled in the art will understand that a non-naturally occurring microbial organism can be produced that secretes the biosynthesized compounds of the invention when grown on a carbon source such as a carbohydrate. Such compounds include, for example, fatty alcohol, fatty aldehyde or fatty acid and any of the intermediate metabolites in the fatty alcohol, fatty aldehyde or fatty acid pathway. All that is required is to engineer in one or more of the required enzyme or protein activities to achieve biosynthesis of the desired compound or intermediate including, for example, inclusion of some or all of the fatty alcohol, fatty aldehyde or fatty acid biosynthetic pathways. Accordingly, the invention provides a non-naturally occurring microbial organism that produces and/or secretes fatty alcohol, fatty aldehyde or fatty acid when grown on a carbohydrate or other carbon source and produces and/or secretes any of the intermediate metabolites shown in the fatty alcohol, fatty aldehyde or fatty acid pathway when grown on a carbohydrate or other carbon source. The fatty alcohol, fatty aldehyde or fatty acid producing microbial organisms of the invention can initiate synthesis from an intermediate, for example, a 3-ketoacyl-CoA, a 3-hydroxyacyl-CoA, an enoyl-CoA, an acyl-CoA, an acyl-ACP, acetate, acetaldehyde, acetyl-phosphate, oxaloacetate, matate, malonate semialdehyde, malonate, malonyl-CoA, acetyl-CoA, or citrate.

The non-naturally occurring microbial organisms of the invention are constructed using methods well known in the art as exemplified herein to exogenously express at least one nucleic acid encoding a fatty alcohol, fatty aldehyde or fatty acid pathway enzyme or protein in sufficient amounts to produce fatty alcohol, fatty aldehyde or fatty acid. It is understood that the microbial organisms of the invention are cultured under conditions sufficient to produce fatty alcohol, fatty aldehyde or fatty acid. Following the teachings and guidance provided herein, the non-naturally occurring microbial organisms of the invention can achieve biosynthesis of fatty alcohol, fatty aldehyde or fatty acid resulting in intracellular concentrations between about 0.1-200 mM or more. Generally, the intracellular concentration of fatty alcohol, fatty aldehyde or fatty acid is between about 3-150 mM, particularly between about 5-125 mM and more particularly between about 8-100 mM, including about 10 mM, 20 mM, 50 mM, 80 mM, or more. Intracellular concentrations between and above each of these exemplary ranges also can be achieved from the non-naturally occurring microbial organisms of the invention.

In some embodiments, culture conditions include anaerobic or substantially anaerobic growth or maintenance conditions. Exemplary anaerobic conditions have been described previously and are well known in the art. Exemplary anaerobic conditions for fermentation processes are described herein and are described, for example, in U.S. publication 2009/0047719, filed Aug. 10, 2007. Any of these conditions can be employed with the non-naturally occurring microbial organisms as well as other anaerobic conditions well known in the art. Under such anaerobic or substantially anaerobic conditions, the fatty alcohol, fatty aldehyde or fatty acid producers can synthesize fatty alcohol, fatty aldehyde or fatty acid at intracellular concentrations of 5-10 mM or more as well as all other concentrations exemplified herein. It is understood that, even though the above description refers to intracellular concentrations, fatty alcohol, fatty aldehyde or fatty acid producing microbial organisms can produce fatty alcohol, fatty aldehyde or fatty acid intracellularly and/or secrete the product into the culture medium.

In addition to the culturing and fermentation conditions disclosed herein, growth condition for achieving biosynthesis of fatty alcohol, fatty aldehyde or fatty acid can include the addition of an osmoprotectant to the culturing conditions. In certain embodiments, the non-naturally occurring microbial organisms of the invention can be sustained, cultured or fermented as described herein in the presence of an osmoprotectant. Briefly, an osmoprotectant refers to a compound that acts as an osmolyte and helps a microbial organism as described herein survive osmotic stress. Osmoprotectants include, but are not limited to, betaines, amino acids, and the sugar trehalose. Non-limiting examples of such are glycine betaine, praline betaine, dimethylthetin, dimethylslfonioproprionate, 3-dimethylsulfonio-2-methylproprionate, pipecolic acid, dimethylsulfonioacetate, choline, L-carnitine and ectoine. In one aspect, the osmoprotectant is glycine betaine. It is understood to one of ordinary skill in the art that the amount and type of osmoprotectant suitable for protecting a microbial organism described herein from osmotic stress will depend on the microbial organism used. The amount of osmoprotectant in the culturing conditions can be, for example, no more than about 0.1 mM, no more than about 0.5 mM, no more than about 1.0 mM, no more than about 1.5 mM, no more than about 2.0 mM, no more than about 2.5 mM, no more than about 3.0 mM, no more than about 5.0 mM, no more than about 7.0 mM, no more than about 10 mM, no more than about 50 mM, no more than about 100 mM or no more than about 500 mM.

In some embodiments, the carbon feedstock and other cellular uptake sources such as phosphate, ammonia, sulfate, chloride and other halogens can be chosen to alter the isotopic distribution of the atoms present in fatty alcohol, fatty aldehyde or fatty acid or any fatty alcohol, fatty aldehyde or fatty acid pathway intermediate. The various carbon feedstock and other uptake sources enumerated above will be referred to herein, collectively, as “uptake sources.” Uptake sources can provide isotopic enrichment for any atom present in the product fatty alcohol, fatty aldehyde or fatty acid or fatty alcohol, fatty aldehyde or fatty acid pathway intermediate, or for side products generated in reactions diverging away from a fatty alcohol, fatty aldehyde or fatty acid pathway. Isotopic enrichment can be achieved for any target atom including, for example, carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, chloride or other halogens.

In some embodiments, the uptake sources can be selected to alter the carbon-12, carbon-13, and carbon-14 ratios. In some embodiments, the uptake sources can be selected to alter the oxygen-16, oxygen-17, and oxygen-18 ratios. In some embodiments, the uptake sources can be selected to alter the hydrogen, deuterium, and tritium ratios. In some embodiments, the uptake sources can be selected to alter the nitrogen-14 and nitrogen-15 ratios. In some embodiments, the uptake sources can be selected to alter the sulfur-32, sulfur-33, sulfur-34, and sulfur-35 ratios. In some embodiments, the uptake sources can be selected to alter the phosphorus-31, phosphorus-32, and phosphorus-33 ratios. In some embodiments, the uptake sources can be selected to alter the chlorine-35, chlorine-36, and chlorine-37 ratios.

In some embodiments, the isotopic ratio of a target atom can be varied to a desired ratio by selecting one or more uptake sources. An uptake source can be derived from a natural source, as found in nature, or from a man-made source, and one skilled in the art can select a natural source, a man-made source, or a combination thereof, to achieve a desired isotopic ratio of a target atom. An example of a man-made uptake source includes, for example, an uptake source that is at least partially derived from a chemical synthetic reaction. Such isotopically enriched uptake sources can be purchased commercially or prepared in the laboratory and/or optionally mixed with a natural source of the uptake source to achieve a desired isotopic ratio. In some embodiments, a target atom isotopic ratio of an uptake source can be achieved by selecting a desired origin of the uptake source as found in nature. For example, as discussed herein, a natural source can be a biobased derived from or synthesized by a biological organism or a source such as petroleum-based products or the atmosphere. In some such embodiments, a source of carbon, for example, can be selected from a fossil fuel-derived carbon source, which can be relatively depleted of carbon-14, or an environmental or atmospheric carbon source, such as CO₂, which can possess a larger amount of carbon-14 than its petroleum-derived counterpart.

The unstable carbon isotope carbon-14 or radiocarbon makes up for roughly 1 in 10¹² carbon atoms in the earth's atmosphere and has a half-life of about 5700 years. The stock of carbon is replenished in the upper atmosphere by a nuclear reaction involving cosmic rays and ordinary nitrogen (¹⁴N). Fossil fuels contain no carbon-14, as it decayed long ago. Burning of fossil fuels lowers the atmospheric carbon-14 fraction, the so-called “Suess effect”.

Methods of determining the isotopic ratios of atoms in a compound are well known to those skilled in the art. Isotopic enrichment is readily assessed by mass spectrometry using techniques known in the art such as accelerated mass spectrometry (AMS), Stable Isotope Ratio Mass Spectrometry (SIRMS) and Site-Specific Natural Isotopic Fractionation by Nuclear Magnetic Resonance (SNIF-NMR). Such mass spectral techniques can be integrated with separation techniques such as liquid chromatography (LC), high performance liquid chromatography (HPLC) and/or gas chromatography, and the like.

In the case of carbon, ASTM D6866 was developed in the United States as a standardized analytical method for determining the biobased content of solid, liquid, and gaseous samples using radiocarbon dating by the American Society for Testing and Materials (ASTM) International. The standard is based on the use of radiocarbon dating for the determination of a product's biobased content. ASTM D6866 was first published in 2004, and the current active version of the standard is ASTM D6866-11 (effective Apr. 1, 2011). Radiocarbon dating techniques are well known to those skilled in the art, including those described herein.

The biobased content of a compound is estimated by the ratio of carbon-14 (¹⁴C) to carbon-12 (¹²C). Specifically, the Fraction Modern (Fm) is computed from the expression: Fm=(S−B)/(M−B), where B, S and M represent the ¹⁴C/¹²C ratios of the blank, the sample and the modern reference, respectively. Fraction Modern is a measurement of the deviation of the ¹⁴C/¹²C ratio of a sample from “Modern.” Modern is defined as 95% of the radiocarbon concentration (in AD 1950) of National Bureau of Standards (NBS) Oxalic Acid I (i.e., standard reference materials (SRM) 4990b) normalized to δ¹³C_(VPDB)=−19 per mil (Olsson, The use of Oxalic acid as a Standard. in, Radiocarbon Variations and Absolute Chronology, Nobel Symposium, 12th Proc., John Wiley & Sons, New York (1970)). Mass spectrometry results, for example, measured by ASM, are calculated using the internationally agreed upon definition of 0.95 times the specific activity of NBS Oxalic Acid I (SRM 4990b) normalized to δ¹³C_(VPDB)=−19 per mil. This is equivalent to an absolute (AD 1950) ¹⁴C/¹²C ratio of 1.176±0.010×10⁻¹² (Karlen et al., Arkiv Geofysik, 4:465-471 (1968)). The standard calculations take into account the differential uptake of one isotope with respect to another, for example, the preferential uptake in biological systems of C¹² over C¹³ over C¹⁴, and these corrections are reflected as a Fm corrected for δ¹³.

An oxalic acid standard (SRM 4990b or HOx 1) was made from a crop of 1955 sugar beet. Although there were 1000 lbs made, this oxalic acid standard is no longer commercially available. The Oxalic Acid II standard (HOx 2; N.I.S.T designation SRM 4990 C) was made from a crop of 1977 French beet molasses. In the early 1980's, a group of 12 laboratories measured the ratios of the two standards. The ratio of the activity of Oxalic acid II to 1 is 1.2933±0.001 (the weighted mean). The isotopic ratio of HOx II is −17.8 per mille. ASTM D6866-11 suggests use of the available Oxalic Acid II standard SRM 4990 C (Hox2) for the modern standard (see discussion of original vs. currently available oxalic acid standards in Mann, Radiocarbon, 25(2):519-527 (1983)). A Fm=0% represents the entire lack of carbon-14 atoms in a material, thus indicating a fossil (for example, petroleum based) carbon source. A Fm=100%, after correction for the post-1950 injection of carbon-14 into the atmosphere from nuclear bomb testing, indicates an entirely modern carbon source. As described herein, such a “modern” source includes biobased sources.

As described in ASTM D6866, the percent modern carbon (pMC) can be greater than 100% because of the continuing but diminishing effects of the 1950s nuclear testing programs, which resulted in a considerable enrichment of carbon-14 in the atmosphere as described in ASTM D6866-11. Because all sample carbon-14 activities are referenced to a “pre-bomb” standard, and because nearly all new biobased products are produced in a post-bomb environment, all pMC values (after correction for isotopic fraction) must be multiplied by 0.95 (as of 2010) to better reflect the true biobased content of the sample. A biobased content that is greater than 103% suggests that either an analytical error has occurred, or that the source of biobased carbon is more than several years old.

ASTM D6866 quantifies the biobased content relative to the material's total organic content and does not consider the inorganic carbon and other non-carbon containing substances present. For example, a product that is 50% starch-based material and 50% water would be considered to have a Biobased Content=100% (50% organic content that is 100% biobased) based on ASTM D6866. In another example, a product that is 50% starch-based material, 25% petroleum-based, and 25% water would have a Biobased Content=66.7% (75% organic content but only 50% of the product is biobased). In another example, a product that is 50% organic carbon and is a petroleum-based product would be considered to have a Biobased Content=0% (50% organic carbon but from fossil sources). Thus, based on the well known methods and known standards for determining the biobased content of a compound or material, one skilled in the art can readily determine the biobased content and/or prepared downstream products that utilize of the invention having a desired biobased content.

Applications of carbon-14 dating techniques to quantify bio-based content of materials are known in the art (Currie et al., Nuclear Instruments and Methods in Physics Research B, 172:281-287 (2000)). For example, carbon-14 dating has been used to quantify bio-based content in terephthalate-containing materials (Colonna et al., Green Chemistry, 13:2543-2548 (2011)). Notably, polypropylene terephthalate (PPT) polymers derived from renewable 1,3-propanediol and petroleum-derived terephthalic acid resulted in Fm values near 30% (i.e., since 3/11 of the polymeric carbon derives from renewable 1,3-propanediol and 8/11 from the fossil end member terephthalic acid) (Currie et al., supra, 2000). In contrast, polybutylene terephthalate polymer derived from both renewable 1,4-butanediol and renewable terephthalic acid resulted in bio-based content exceeding 90% (Colonna et al., supra, 2011).

Accordingly, in some embodiments, the present invention provides fatty alcohol, fatty aldehyde or fatty acid or a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate that has a carbon-12, carbon-13, and carbon-14 ratio that reflects an atmospheric carbon, also referred to as environmental carbon, uptake source. For example, in some aspects the fatty alcohol, fatty aldehyde or fatty acid or a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate can have an Fm value of at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98% or as much as 100%. In some such embodiments, the uptake source is CO₂. In some embodiments, the present invention provides fatty alcohol, fatty aldehyde or fatty acid or a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate that has a carbon-12, carbon-13, and carbon-14 ratio that reflects petroleum-based carbon uptake source. In this aspect, the fatty alcohol, fatty aldehyde or fatty acid or a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate can have an Fm value of less than 95%, less than 90%, less than 85%, less than 80%, less than 75%, less than 70%, less than 65%, less than 60%, less than 55%, less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, less than 2% or less than 1%. In some embodiments, the present invention provides fatty alcohol, fatty aldehyde or fatty acid or a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate that has a carbon-12, carbon-13, and carbon-14 ratio that is obtained by a combination of an atmospheric carbon uptake source with a petroleum-based uptake source. Using such a combination of uptake sources is one way by which the carbon-12, carbon-13, and carbon-14 ratio can be varied, and the respective ratios would reflect the proportions of the uptake sources.

Further, the present invention relates to the biologically produced fatty alcohol, fatty aldehyde or fatty acid or fatty alcohol, fatty aldehyde or fatty acid pathway intermediate as disclosed herein, and to the products derived therefrom, wherein the fatty alcohol, fatty aldehyde or fatty acid or a fatty alcohol, fatty aldehyde or fatty acid pathway intermediate has a carbon-12, carbon-13, and carbon-14 isotope ratio of about the same value as the CO₂ that occurs in the environment. For example, in some aspects the invention provides bioderived fatty alcohol, fatty aldehyde or fatty acid or a bioderived fatty alcohol, fatty aldehyde or fatty acid intermediate having a carbon-12 versus carbon-13 versus carbon-14 isotope ratio of about the same value as the CO₂ that occurs in the environment, or any of the other ratios disclosed herein. It is understood, as disclosed herein, that a product can have a carbon-12 versus carbon-13 versus carbon-14 isotope ratio of about the same value as the CO₂ that occurs in the environment, or any of the ratios disclosed herein, wherein the product is generated from bioderived fatty alcohol, fatty aldehyde or fatty acid or a bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate as disclosed herein, wherein the bioderived product is chemically modified to generate a final product. Methods of chemically modifying a bioderived product of fatty alcohol, fatty aldehyde or fatty acid, or an intermediate thereof, to generate a desired product are well known to those skilled in the art, as described herein. The invention further provides biofuels, chemicals, polymers, surfactants, soaps, detergents, shampoos, lubricating oil additives, fragrances, flavor materials or acrylates having a carbon-12 versus carbon-13 versus carbon-14 isotope ratio of about the same value as the CO₂ that occurs in the environment, wherein the biofuels, chemicals, polymers, surfactants, soaps, detergents, shampoos, lubricating oil additives, fragrances, flavor materials or acrylates are generated directly from or in combination with bioderived fatty alcohol, fatty aldehyde or fatty acid or a bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate as disclosed herein.

Fatty alcohol, fatty aldehyde or fatty acid is a chemical used in commercial and industrial applications. Non-limiting examples of such applications include production of biofuels, chemicals, polymers, surfactants, soaps, detergents, shampoos, lubricating oil additives, fragrances, flavor materials and acrylates. Accordingly, in some embodiments, the invention provides biobased biofuels, chemicals, polymers, surfactants, soaps, detergents, shampoos, lubricating oil additives, fragrances, flavor materials and acrylates comprising one or more bioderived fatty alcohol, fatty aldehyde or fatty acid or bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate produced by a non-naturally occurring microorganism of the invention or produced using a method disclosed herein.

As used herein, the term “bioderived” means derived from or synthesized by a biological organism and can be considered a renewable resource since it can be generated by a biological organism. Such a biological organism, in particular the microbial organisms of the invention disclosed herein, can utilize feedstock or biomass, such as, sugars or carbohydrates obtained from an agricultural, plant, bacterial, or animal source. Alternatively, the biological organism can utilize atmospheric carbon. As used herein, the term “biobased” means a product as described above that is composed, in whole or in part, of a bioderived compound of the invention. A biobased or bioderived product is in contrast to a petroleum derived product, wherein such a product is derived from or synthesized from petroleum or a petrochemical feedstock.

In some embodiments, the invention provides a biofuel, chemical, polymer, surfactant, soap, detergent, shampoo, lubricating oil additive, fragrance, flavor material or acrylate comprising bioderived fatty alcohol, fatty aldehyde or fatty acid or bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate, wherein the bioderived fatty alcohol, fatty aldehyde or fatty acid or bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate includes all or part of the fatty alcohol, fatty aldehyde or fatty acid or fatty alcohol, fatty aldehyde or fatty acid pathway intermediate used in the production of a biofuel, chemical, polymer, surfactant, soap, detergent, shampoo, lubricating oil additive, fragrance, flavor material or acrylate. Thus, in some aspects, the invention provides a biobased biofuel, chemical, polymer, surfactant, soap, detergent, shampoo, lubricating oil additive, fragrance, flavor material or acrylate comprising at least 2%, at least 3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98% or 100% bioderived fatty alcohol, fatty aldehyde or fatty acid or bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate as disclosed herein. Additionally, in some aspects, the invention provides a biobased biofuel, chemical, polymer, surfactant, soap, detergent, shampoo, lubricating oil additive, fragrance, flavor material or acrylate wherein the fatty alcohol, fatty aldehyde or fatty acid or fatty alcohol, fatty aldehyde or fatty acid pathway intermediate used in its production is a combination of bioderived and petroleum derived fatty alcohol, fatty aldehyde or fatty acid or fatty alcohol, fatty aldehyde or fatty acid pathway intermediate. For example, a biobased a biofuel, chemical, polymer, surfactant, soap, detergent, shampoo, lubricating oil additive, fragrance, flavor material or acrylate can be produced using 50% bioderived fatty alcohol, fatty aldehyde or fatty acid and 50% petroleum derived fatty alcohol, fatty aldehyde or fatty acid or other desired ratios such as 60%/40%, 70%/30%, 80%/20%, 90%/10%, 95%/5%, 100%/0%, 40%/60%, 30%/70%, 20%/80%, 10%/90% of bioderived/petroleum derived precursors, so long as at least a portion of the product comprises a bioderived product produced by the microbial organisms disclosed herein. It is understood that methods for producing a biofuel, chemical, polymer, surfactant, soap, detergent, shampoo, lubricating oil additive, fragrance, flavor material or acrylate using the bioderived fatty alcohol, fatty aldehyde or fatty acid or bioderived fatty alcohol, fatty aldehyde or fatty acid pathway intermediate of the invention are well known in the art.

The culture conditions can include, for example, liquid culture procedures as well as fermentation and other large scale culture procedures. As described herein, particularly useful yields of the biosynthetic products of the invention can be obtained under anaerobic or substantially anaerobic culture conditions.

As described herein, one exemplary growth condition for achieving biosynthesis of fatty alcohol, fatty aldehyde or fatty acid includes anaerobic culture or fermentation conditions. In certain embodiments, the non-naturally occurring microbial organisms of the invention can be sustained, cultured or fermented under anaerobic or substantially anaerobic conditions. Briefly, anaerobic conditions refers to an environment devoid of oxygen. Substantially anaerobic conditions include, for example, a culture, batch fermentation or continuous fermentation such that the dissolved oxygen concentration in the medium remains between 0 and 10% of saturation. Substantially anaerobic conditions also includes growing or resting cells in liquid medium or on solid agar inside a sealed chamber maintained with an atmosphere of less than 1% oxygen. The percent of oxygen can be maintained by, for example, sparging the culture with an N₂/CO₂ mixture or other suitable non-oxygen gas or gases.

The culture conditions described herein can be scaled up and grown continuously for manufacturing of fatty alcohol, fatty aldehyde or fatty acid. Exemplary growth procedures include, for example, fed-batch fermentation and batch separation; fed-batch fermentation and continuous separation, or continuous fermentation and continuous separation. All of these processes are well known in the art. Fermentation procedures are particularly useful for the biosynthetic production of commercial quantities of fatty alcohol, fatty aldehyde or fatty acid. Generally, and as with non-continuous culture procedures, the continuous and/or near-continuous production of fatty alcohol, fatty aldehyde or fatty acid will include culturing a non-naturally occurring fatty alcohol, fatty aldehyde or fatty acid producing organism of the invention in sufficient nutrients and medium to sustain and/or nearly sustain growth in an exponential phase. Continuous culture under such conditions can include, for example, growth for 1 day, 2, 3, 4, 5, 6 or 7 days or more. Additionally, continuous culture can include longer time periods of 1 week, 2, 3, 4 or 5 or more weeks and up to several months. Alternatively, organisms of the invention can be cultured for hours, if suitable for a particular application. It is to be understood that the continuous and/or near-continuous culture conditions also can include all time intervals in between these exemplary periods. It is further understood that the time of culturing the microbial organism of the invention is for a sufficient period of time to produce a sufficient amount of product for a desired purpose.

Fermentation procedures are well known in the art. Briefly, fermentation for the biosynthetic production of fatty alcohol, fatty aldehyde or fatty acid can be utilized in, for example, fed-batch fermentation and batch separation; fed-batch fermentation and continuous separation, or continuous fermentation and continuous separation. Examples of batch and continuous fermentation procedures are well known in the art.

In addition to the above fermentation procedures using the fatty alcohol, fatty aldehyde or fatty acid producers of the invention for continuous production of substantial quantities of fatty alcohol, fatty aldehyde or fatty acid, the fatty alcohol, fatty aldehyde or fatty acid producers also can be, for example, simultaneously subjected to chemical synthesis procedures to convert the product to other compounds or the product can be separated from the fermentation culture and sequentially subjected to chemical or enzymatic conversion to convert the product to other compounds, if desired.

In addition to active and selective enzymes producing fatty alcohols, fatty aldehydes, or fatty acids at high yield, titer and productivity, a robust host organism that can efficiently direct carbon and reducing equivalents to fatty alcohol, fatty aldehyde and fatty acid biosynthesis can be beneficial. Host modifications described herein are particularly useful in combination with selective enzymes described herein that favor formation of the desired fatty alcohol, fatty aldehyde, or fatty acid product. Several host modifications described herein entail introducing heterologous enzyme activities into the host organism. Other modifications involve overexpressing or elevating enzyme activity relative to wild type levels. Yet other modifications include disrupting endogenous genes or attenuating endogenous enzyme activities.

In one embodiment of the invention, the microbial organisms efficiently directs carbon and energy sources into production of acetyl-CoA, which is used as both a primer and extension unit in the MI-FAE cycle. In unmodified microbial organism, fatty alcohol, fatty aldehyde and fatty acid production in the cytosol relies on the native cell machinery to provide the necessary precursors. Thus, high concentrations of cytosolic acetyl-CoA are desirable for facilitating deployment of a cytosolic fatty alcohol, fatty aldehyde or fatty acid production pathway that originates from acetyl-CoA. Metabolic engineering strategies for increasing cytosolic acetyl-CoA are disclosed herein.

Since many eukaryotic organisms synthesize most of their acetyl-CoA in the mitochondria during growth on glucose, increasing the availability of acetyl-CoA in the cytosol can be obtained by introduction of a cytosolic acetyl-CoA biosynthesis pathway. Accordingly, acetyl-CoA biosynthesis pathways are described herein. In one embodiment, utilizing the pathways shown in FIG. 2, acetyl-CoA can be synthesized in the cytosol from a pyruvate or threonine precursor. In other embodiment, acetyl-CoA can be synthesized in the cytosol from phosphoenolpyruvate (PEP) or pyruvate (FIG. 3). In yet another embodiment acetyl-CoA can be synthesized in cellular compartments and transported to the cytosol. For example, one mechanism involves converting mitochondrial acetyl-CoA to a metabolic intermediate such as citrate or citramalate, transporting those intermediates to the cytosol, and then regenerating the acetyl-CoA (see FIGS. 4 and 5). Exemplary acetyl-CoA pathways and corresponding enzymes are further described in Examples II-IV.

In another embodiment, increasing cytosolic acetyl-CoA availability for fatty alcohol, fatty aldehyde, or fatty acid biosynthesis is to disrupt or attenuate competing enzymes and pathways that utilize acetyl-CoA or its precursors. Exemplary competing enzyme activities include, but are not limited to, pyruvate decarboxylase, lactate dehydrogenase, short-chain aldehyde and alcohol dehydrogenases, acetate kinase, phosphotransacetylase, glyceraldehyde-3-phosphate dehydrogenases, pyruvate oxidase and acetyl-CoA carboxylase. Exemplary acetyl-CoA consuming pathways whose disruption or attenuation can improve fatty alcohol, fatty aldehyde, or fatty acid production include the mitochondrial TCA cycle, fatty acid biosynthesis, ethanol production and amino acid biosynthesis. These enzymes and pathways are further described herein.

Yet another strategy for increasing cytosolic acetyl-CoA production is to increase the pool of CoA available in the cytoplasm. This can be accomplished by overexpression of CoA biosynthetic enzymes in the cytosol. In particular, expression of pantothenate kinase (EC 2.7.1.33) can be used. This enzyme catalyzes the first step and rate-limiting enzyme of CoA biosynthesis. Exemplary pantothenate kinase variants resistant to feedback inhibition by CoA are well known in the art (Rock et al, J Bacteriol 185: 3410-5 (2003)) and are described in the below table.

Protein Accession # GI number Organism coaA AAC76952 1790409 Escherichia coli CAB1 NP_010820.3 398366683 Saccharomyces cerevisiae KLLA0C00869g XP_452233.1 50304555 Kluyveromyces lactis YALI0D25476g XP_503275.1 50551601 Yarrowia lipolytica ANI_1_3272024 XP_001400486.2 317028058 Aspergillus niger

Competing enzymes and pathways that divert acyl-CoA substrates from production of fatty alcohols, fatty aldehydes or fatty acids of the invention can also be attenuated or disrupted. Exemplary enzymes for attenuation include acyltransferases, carnitine shuttle enzymes and negative regulators of MI-FAE cycle or termination pathway enzymes.

Disruption or attenuation of acyltransferases that transfer acyl moieties from CoA to other acceptors such as ACP, glycerol, ethanol and others, can increase the availability of acyl-CoA for fatty alcohol, fatty aldehyde or fatty acid production. For example, Acyl-CoA:ACP transacylase (EC 2.3.1.38; 2.3.1.39) enzymes such as fabH (KASIII) of E. coli transfer acyl moieties from CoA to ACP. FabH is active on acetyl-CoA and butyryl-CoA (Prescott et al, Adv. Enzymol. Relat. Areas Mol, 36:269-311 (1972)). Acetyl-CoA:ACP transacylase enzymes from Plasmodium falciparum and Streptomyces avermitillis have been heterologously expressed in E. coli (Lobo et al, Biochem 40:11955-64 (2001)). A synthetic KASIII (FabH) from P. falciparum expressed in a fabH-deficient Lactococcus lactis host was able to complement the native fadH activity (Du et al, AEM 76:3959-66 (2010)). The acetyl-CoA:ACP transacylase enzyme from Spinacia oleracea accepts other acyl-ACP molecules as substrates, including butyryl-ACP (Shimakata et al, Methods Enzym 122:53-9 (1986)). Malonyl-CoA:ACP transacylase enzymes include FabD of E. coli and Brassica napsus (Verwoert et al, J Bacteriol, 174:2851-7 (1992); Simon et al, FEBS Lett 435:204-6 (1998)). FabD of B. napsus was able to complement fabD-deficient E. coli. The multifunctional eukaryotic fatty acid synthase enzyme complexes (described herein) also catalyze this activity. Other exemplary acyltransferases include diacylglycerol acyltransferases such as LRO1 and DGA1 of S. cerevisiae and DGA1 and DGA2 of Yarrowia lipolytica, glycerolipid acyltransferase enzymes such as plsB of E. coli (GenBank: AAC77011.2, GI:87082362; Heath and Rock, J Bacteriol 180:1425-30 (1998)), sterol acyltransferases such as ARE1 and ARE2 of S. cerevisiae, ethanol acyltransferases (EEB1, EHT1), putative acyltransferases (YMR210W) and others.

Protein GenBank ID GI Number Organism fabH AAC74175.1 1787333 Escherichia coli fadA NP_824032.1 29829398 Streptomyces avermitillis fabH AAC63960.1 3746429 Plasmodium falciparum Synthetic ACX34097.1 260178848 Plasmodium falciparum construct fabH CAL98359.1 124493385 Lactococcus lactis fabD AAC74176.1 1787334 Escherichia coli fabD CAB45522.1 5139348 Brassica napsus LRO1 NP_014405.1 6324335 Saccharomyces cerevisiae DGA1 NP_014888.1 6324819 Saccharomyces cerevisiae DGA1 CAG79269.1 49649549 Yarrowia lipolytica DGA2 XP_504700.1 50554583 Yarrowia lipolytica ARE1 NP_009978.1 6319896 Saccharomyces cerevisiae ARE2 NP_014416.1 6324346 Saccharomyces cerevisiae EEB1 NP_015230.1 6325162 Saccharomyces cerevisiae EHT1 NP_009736.3 398365307 Saccharomyces cerevisiae YMR210W NP_013937.1 6323866 Saccharomyces cerevisiae ALE1 NP_014818.1 6324749 Saccharomyces cerevisiae

Increasing production of fatty alcohols, fatty aldehydes or fatty acids may necessitate disruption or attenuation of enzymes involved in the trafficking of acetyl-CoA and acyl-CoA molecules from the cytosol to other compartments of the organism such as mitochondria, endoplasmic reticulum, proteoliposomes and peroxisomes. In these compartments, the acyl-CoA intermediate can be degraded or used as building blocks to synthesize fatty acids, cofactors and other byproducts.

Acetyl-CoA and acyl-CoA molecules localized in the cytosol can be transported into other cellular compartments with the aid of the carrier molecule carnitine via carnitine shuttles (van Roermund et al., EMBO J 14:3480-86 (1995)). Acyl-carnitine shuttles between cellular compartments have been characterized in yeasts such as Candida albicans (Strijbis et al, J Biol Chem 285:24335-46 (2010)). In these shuttles, the acyl moiety of acyl-CoA is reversibly transferred to carnitine by acylcarnitine transferase enzymes. Acetylcarnitine can then be transported across the membrane by organelle-specific acylcarnitine/carnitine translocase enzymes. After translocation, the acyl-CoA is regenerated by acetylcarnitine transferase. Enzymes suitable for disruption or attenuation include carnitine acyltransferase enzymes, acylcarnitine translocases, acylcarnitine carrier proteins and enzymes involved in carnitine biosynthesis.

Carnitine acetyltransferase (CAT, EC 2.3.1.7) reversibly links acetyl units from acetyl-CoA to the carrier molecule, carnitine. Candida albicans encodes three CAT isozymes: Cat2, Yat1 and Yat2 (Strijbis et al., J Biol Chem 285:24335-46 (2010)). Cat2 is expressed in both the mitochondrion and the peroxisomes, whereas Yat1 and Yat2 are cytosolic. The Cat2 transcript contains two start codons that are regulated under different carbon source conditions. The longer transcript contains a mitochondrial targeting sequence whereas the shorter transcript is targeted to peroxisomes. Cat2 of Saccharomyces cerevisiae and AcuJ of Aspergillus nidulans employ similar mechanisms of dual localization (Elgersma et al., EMBO J 14:3472-9 (1995); Hynes et al., Euk Cell 10:547-55 (2011)). The cytosolic CAT of A. nidulans is encoded by facC. Other exemplary CAT enzymes are found in Rattus norvegicus and Homo sapiens (Cordente et al., Biochem 45:6133-41 (2006)). Exemplary carnitine acyltransferase enzymes (EC 2.3.1.21) are the Cpt1 and Cpt2 gene products of Rattus norvegicus (de Vries et al., Biochem 36:5285-92 (1997)).

Protein Accession # GI number Organism Cat2 AAN31660.1 23394954 Candida albicans Yat1 AAN31659.1 23394952 Candida albicans Yat2 XP_711005.1 68490355 Candida albicans Cat2 CAA88327.1 683665 Saccharomyces cerevisiae Yat1 AAC09495.1 456138 Saccharomyces cerevisiae Yat2 NP_010941.1 6320862 Saccharomyces cerevisiae AcuJ CBF69795.1 259479509 Aspergillus nidulans FacC AAC82487.1 2511761 Aspergillus nidulans Crat AAH83616.1 53733439 Rattus norvegicus Crat P43155.5 215274265 Homo sapiens Cpt1 AAB48046.1 1850590 Rattus norvegicus Cpt2 AAB02339.1 1374784 Rattus norvegicus

Carnitine-acylcarnitine translocases can catalyze the bidirectional transport of carnitine and carnitine-fatty acid complexes. The Cact gene product provides a mechanism for transporting acyl-carnitine substrates across the mitochondrial membrane (Ramsay et al Biochim Biophys Acta 1546:21-42 (2001)). A similar protein has been studied in humans (Sekoguchi et al., J Biol Chem 278:38796-38802 (2003)). The Saccharomyces cerevisiae mitochondrial carnitine carrier is Crc1 (van Roermund et al., supra; Palmieri et al., Biochimica et Biophys Acta 1757:1249-62 (2006)). The human carnitine translocase was able to complement a Crc1-deficient strain of S. cerevisiae (van Roermund et al., supra). Two additional carnitine translocases found in Drosophila melanogaster and Caenorhabditis elegans were also able to complement Crc1-deficient yeast (Oey et al., Mol Genet Metab 85:121-24 (2005)). Four mitochondrial carnitine/acetylcarnitine carriers were identified in Trypanosoma brucei based on sequence homology to the yeast and human transporters (Colasante et al., Mol Biochem Parasit 167:104-117 (2009)). The carnitine transporter of Candida albicans was also identified by sequence homology. An additional mitochondrial carnitine transporter is the acuH gene product of Aspergillus nidulans, which is exclusively localized to the mitochondrial membrane (Lucas et al., FEMS Microbiol Lett 201:193-8 (2006)).

Protein GenBank ID GI Number Organism Cact P97521.1 2497984 Rattus norvegicus Cacl NP_001034444.1 86198310 Homo sapiens CaO19.2851 XP_715782.1 68480576 Candida albicans Crc1 NP_014743.1 6324674 Saccharomyces cerevisiae Dif-1 CAA88283.1 829102 Caenorhabditis elegans colt CAA73099.1 1944534 Drosophila melanogaster Tb11.02.2960 EAN79492.1 70833990 Trypanosoma brucei Tb11.03.0870 EAN79007.1 70833505 Trypanosoma brucei Tb11.01.5040 EAN80288.1 70834786 Trypanosoma brucei Tb927.8.5810 AAX69329.1 62175181 Trypanosoma brucei acuH CAB44434.1 5019305 Aspergillus nidulans

Transport of carnitine and acylcarnitine across the peroxisomal membrane has not been well-characterized. Specific peroxisomal acylcarnitine carrier proteins in yeasts have not been identified to date. However, mitochondrial carnitine translocases can also function in the peroxisomal transport of carnitine and acetylcarnitine. Experimental evidence suggests that the OCTN3 protein of Mus musculus is a peroxisomal carnitine/acylcarnitine translocase.

Yet another possibility is that acyl-CoA or acyl-carnitine are transported across the peroxisomal or mitochondrial membranes by an acyl-CoA transporter such as the Pxa1 and Pxa2 ABC transporter of Saccharomyces cerevisiae or the ALDP ABC transporter of Homo sapiens (van Roermund et al., FASEB J 22:4201-8 (2008)). Pxa1 and Pxa2 (Pat1 and Pat2) form a heterodimeric complex in the peroxisomal membrane and catalyze the ATP-dependent transport of fatty acyl-CoA esters into the peroxisome (Verleur et al., Eur J Biochem 249: 657-61 (1997)). The mutant phenotype of a pxa1/pxa2 deficient yeast can be rescued by heterologous expression of ALDP, which was shown to transport a range of acyl-CoA substrates (van Roermund et al., FASEB J 22:4201-8 (2008)). Deletion of the Pxa12 transport system, in tandem with deletion of the peroxisomal fatty acyl-CoA synthetase (Faa2) abolished peroxisomal beta-oxidation in S. cerevisiae. Yet another strategy for reducing transport of pathway intermediates or products into the peroxisome is to attenuate or eliminate peroxisomal function, by interfering with systems involved in peroxisomal biogenesis. An exemplary target is Pex10 of Yarrowia lipolytica and homologs.

Protein Accession # GI number Organism OCTN3 BAA78343.1 4996131 Mus musculus Pxa1 AAC49009.1 619668 Saccharomyces cerevisiae Pxa2 AAB51597.1 1931633 Saccharomyces cerevisiae Faa2 NP_010931.3 398364331 Saccharomyces cerevisiae ALDP NP_000024.2 7262393 Homo sapiens Pex10 BAA99413.1 9049374 Yarrowia lipolytica

Carnitine biosynthetic pathway enzymes are also suitable candidates for disruption or attenuation. In Candida albicans, for example, carnitine is synthesized from trimethyl-L-lysine in four enzymatic steps (Strijbis et al., FASEB J 23:2349-59 (2009)). The carnitine pathway precursor, trimethyllysine (TML), is produced during protein degradation. TML dioxygenase (CaO13.4316) hydroxylates TML to form 3-hydroxy-6-N-trimethyllysine. A pyridoxal-5′-phosphate dependent aldolase (CaO19.6305) then cleaves HTML into 4-trimethylaminobutyraldehyde. The 4-trimethylaminobutyraldehyde is subsequently oxidized to 4-trimethylaminobutyrate by a dehydrogenase (CaO19.6306). In the final step, 4-trimethylaminobutyrate is hydroxylated to form carnitine by the gene product of CaO19.7131. Flux through the carnitine biosynthesis pathway is limited by the availability of the pathway substrate and very low levels of carnitine seem to be sufficient for normal carnitine shuttle activity (Strejbis et al., IUBMB Life 62:357-62 (2010)).

Protein Accession # GI number Organism CaO19.4316 XP_720623.1 68470755 Candida albicans CaO19.6305 XP_711090.1 68490151 Candida albicans CaO19.6306 XP_711091.1 68490153 Candida albicans CaO19.7131 XP_715182.1 68481628 Candida albicans

Carbon flux towards production of fatty alcohols, fatty aldehydes or fatty acids can be improved by deleting or attenuating competing pathways. Typical fermentation products of yeast include ethanol, glycerol and CO₂. The elimination or reduction of these byproducts can be accomplished by approaches described herein. For example, carbon loss due to respiration can be reduced. Other potential byproducts include lactate, acetate, formate, fatty acids and amino acids.

The conversion of acetyl-CoA into ethanol can be detrimental to the production of fatty alcohols, fatty aldehyes or fatty acids because the conversion process can draw away both carbon and reducing equivalents from the MI-FAE cycle and termination pathway. Ethanol can be formed from pyruvate in two enzymatic steps catalyzed by pyruvate decarboxylase and ethanol dehydrogenase. Saccharomyces cerevisiae has three pyruvate decarboxylases (PDC1, PDC5 and PDC6). PDC1 is the major isozyme and is strongly expressed in actively fermenting cells. PDC5 also functions during glycolytic fermentation, but is expressed only in the absence of PDC1 or under thiamine limitating conditions. PDC6 functions during growth on nonfermentable carbon sources. Deleting PDC 1 and PDC5 can reduce ethanol production significantly; however these deletions can lead to mutants with increased PDC6 expression. Deletion of all three eliminates ethanol formation completely but also can cause a growth defect because of inability of the cells to form sufficient acetyl-CoA for biomass formation. This, however, can be overcome by evolving cells in the presence of reducing amounts of C2 carbon source (ethanol or acetate) (van Maris et al, AEM 69:2094-9 (2003)). It has also been reported that deletion of the positive regulator PDC2 of pyruvate decarboxylases PDC1 and PDC5, reduced ethanol formation to ˜10% of that made by wild-type (Hohmann et al, Mol Gen Genet. 241:657-66 (1993)). Protein sequences and identifiers of PDC enzymes are listed in Example II.

Alternatively, alcohol dehydrogenases that convert acetaldehyde into ethanol and/or other short chain alcohol dehydrogenases can be disrupted or attenuated to provide carbon and reducing equivalents for the MI-FAE cycle or termination pathway. To date, seven alcohol dehydrogenases, ADHI-ADHVII, have been reported in S. cerevisiae (de Smidt et al, FEMS Yeast Res 8:967-78 (2008)). ADH1 (GI:1419926) is the key enzyme responsible for reducing acetaldehyde to ethanol in the cytosol under anaerobic conditions. It has been reported that a yeast strain deficient in ADH1 cannot grow anaerobically because an active respiratory chain is the only alternative path to regenerate NADH and lead to a net gain of ATP (Drewke et al, J Bacteriol 172:3909-17 (1990)). This enzyme is an ideal candidate for downregulation to limit ethanol production. ADH2 is severely repressed in the presence of glucose. In K. lactis, two NAD-dependent cytosolic alcohol dehydrogenases have been identified and characterized. These genes also show activity for other aliphatic alcohols. The genes ADH1 (GI:113358) and ADHII (GI:51704293) are preferentially expressed in glucose-grown cells (Bozzi et al, Biochim Biophys Acta 1339:133-142 (1997)). Cytosolic alcohol dehydrogenases are encoded by ADH1 (GI:608690) in C. albicans, ADH1 (GI:3810864) in S. pombe, ADH1 (GI:5802617) in Y. lipolytica, ADH1 (GI:2114038) and ADHII (GI:2143328) in Pichia stipitis or Scheffersomyces stipitis (Passoth et al, Yeast 14:1311-23 (1998)). Candidate alcohol dehydrogenases are shown the table below.

Protein GenBank ID GI number Organism SADH BAA24528.1 2815409 Candida parapsilosis ADH1 NP_014555.1 6324486 Saccharomyces cerevisiae s288c ADH2 NP_014032.1 6323961 Saccharomyces cerevisiae s288c ADH3 NP_013800.1 6323729 Saccharomyces cerevisiae s288c ADH4 NP_011258.2 269970305 Saccharomyces cerevisiae s288c ADH5 (SFA1) NP_010113.1 6320033 Saccharomyces cerevisiae s288c ADH6 NP_014051.1 6323980 Saccharomyces cerevisiae s288c ADH7 NP_010030.1 6319949 Saccharomyces cerevisiae s288c adhP CAA44614.1 2810 Kluyveromyces lactis ADH1 P20369.1 113358 Kluyveromyces lactis ADH2 CAA45739.1 2833 Kluyveromyces lactis ADH3 P49384.2 51704294 Kluyveromyces lactis ADH1 CAA57342.1 608690 Candida albicans ADH2 CAA21988.1 3859714 Candida albicans SAD XP_712899.1 68486457 Candida albicans ADH1 CAA21782.1 3810864 Schizosaccharomyces pombe ADH1 AAD51737.1 5802617 Yarrowia lipolytica ADH2 AAD51738.1 5802619 Yarrowia lipolytica ADH3 AAD51739.1 5802621 Yarrowia lipolytica AlcB AAX53105.1 61696864 Aspergillus niger ANI_1_(—) XP_001399347.1 145231748 Aspergillus niger 282024 ANI_1_(—) XP_001398574.2 317037131 Aspergillus niger 126164 ANI_1_(—) XP_001395505.2 317033815 Aspergillus niger 1756104 ADH2 CAA73827.1 2143328 Scheffersomyces stipitis

Attenuation or disruption of one or more glycerol-3-phosphatase or glycerol-3-phosphate (G3P) dehydrogenase enzymes can eliminate or reduce the formation of glycerol, and thereby conserving carbon and reducing equivalents for production of fatty alcohols, fatty aldehydes or fatty acids.

G3P phosphatase catalyzes the hydrolysis of G3P to glycerol. Enzymes with this activity include the glycerol-1-phosphatase (EC 3.1.3.21) enzymes of Saccharomyces cerevisiae (GPP1 and GPP2), Candida albicans and Dunaleilla parva (Popp et al, Biotechnol Bioeng 100:497-505 (2008); Fan et al, FEMS Microbiol Lett 245:107-16 (2005)). The D. parva gene has not been identified to date. These and additional G3P phosphatase enzymes are shown in the table below.

Protein GenBank ID GI Number Organism GPP1 DAA08494.1 285812595 Saccharomyces cerevisiae GPP2 NP_010984.1 6320905 Saccharomyces cerevisiae GPP1 XP_717809.1 68476319 Candida albicans KLLA0C08217g XP_452565.1 50305213 Kluyveromyces lactis KLLA0C11143g XP_452697.1 50305475 Kluyveromyces lactis ANI_1_380074 XP_001392369.1 145239445 Aspergillus niger ANI_1_444054 XP_001390913.2 317029125 Aspergillus niger

S. cerevisiae has three G3P dehydrogenase enzymes encoded by GPD1 and GDP2 in the cytosol and GUT2 in the mitochondrion. GPD2 is known to encode the enzyme responsible for the majority of the glycerol formation and is responsible for maintaining the redox balance under anaerobic conditions. GPD1 is primarily responsible for adaptation of S. cerevisiae to osmotic stress (Bakker et al., FEMS Microbiol Rev 24:15-37 (2001)). Attenuation of GPD1, GPD2 and/or GUT2 will reduce glycerol formation. GPD1 and GUT2 encode G3P dehydrogenases in Yarrowia lipolytica (Beopoulos et al, AEM 74:7779-89 (2008)). GPD1 and GPD2 encode for G3P dehydrogenases in S. pombe. Similarly, G3P dehydrogenase is encoded by CTRG_02011 in Candida tropicalis and a gene represented by GI:20522022 in Candida albicans.

Protein GenBank ID GI number Organism GPD1 CAA98582.1 1430995 Saccharomyces cerevisiae GPD2 NP_014582.1 6324513 Saccharomyces cerevisiae GUT2 NP_012111.1 6322036 Saccharomyces cerevisiae GPD1 CAA22119.1 6066826 Yarrowia lipolytica GUT2 CAG83113.1 49646728 Yarrowia lipolytica GPD1 CAA22119.1 3873542 Schizosaccharo- myces pombe GPD2 CAA91239.1 1039342 Schizosaccharo- myces pombe ANI_1_786014 XP_001389035.2 317025419 Aspergillus niger ANI_1_1768134 XP_001397265.1 145251503 Aspergillus niger KLLA0C04004g XP_452375.1 50304839 Kluyveromyces lactis CTRG_02011 XP_002547704.1 255725550 Candida tropicalis GPD1 XP_714362.1 68483412 Candida albicans GPD2 XP_713824.1 68484586 Candida albicans

Enzymes that form acid byproducts such as acetate, formate and lactate can also be attenuated or disrupted. Such enzymes include acetate kinase, phosphotransacetylase and pyruvate oxidase. Disruption or attenuation of pyruvate formate lyase and formate dehydrogenase could limit formation of formate and carbon dioxide. These enzymes are described in further detail in Example II.

Alcohol dehydrogenases that convert pyruvate to lactate are also candidates for disruption or attenuation. Lactate dehydrogenase enzymes include ldhA of E. coli and ldh from Ralstonia eutropha (Steinbuchel and Schlegel, Eur. J. Biochem. 130:329-334 (1983)). Other alcohol dehydrogenases listed above may also exhibit LDH activity.

Protein GenBank ID GI number Organism ldhA NP_415898.1 16129341 Escherichia coli Ldh YP_725182.1 113866693 Ralstonia eutropha

Tuning down activity of the mitochondrial pyruvate dehydrogenase complex will limit flux into the mitochondrial TCA cycle. Under anaerobic conditions and in conditions where glucose concentrations are high in the medium, the capacity of this mitochondrial enzyme is very limited and there is no significant flux through it. However, in some embodiments, this enzyme can be disrupted or attenuated to increase fatty alcohol, fatty aldehyde or fatty acid production. Exemplary pyruvate dehydrogenase genes include PDB1, PDA1, LAT1 and LPD1. Accession numbers and homologs are listed in Example II.

Another strategy for reducing flux into the TCA cycle is to limit transport of pyruvate into the mitochondria by tuning down or deleting the mitochondrial pyruvate carrier. Transport of pyruvate into the mitochondria in S. cerevisiae is catalyzed by a heterocomplex encoded by MPC1 and MPC2 (Herzig et al, Science 337:93-6 (2012); Bricker et al, Science 337:96-100 (2012)). S. cerevisiae encodes five other putative monocarboxylate transporters (MCH1-5), several of which may be localized to the mitochondrial membrane (Makuc et al, Yeast 18:1131-43 (2001)). NDT1 is another putative pyruvate transporter, although the role of this protein is disputed in the literature (Todisco et al, J Biol Chem 20:1524-31 (2006)). Exemplary pyruvate and monocarboxylate transporters are shown in the table below:

Protein GenBank ID GI number Organism MPC1 NP_011435.1 6321358 Saccharomyces cerevisiae MPC2 NP_012032.1 6321956 Saccharomyces cerevisiae MPC1 XP_504811.1 50554805 Yarrowia lipolytica MPC2 XP_501390.1 50547841 Yarrowia lipolytica MPC1 XP_719951.1 68471816 Candida albicans MPC2 XP_716190.1 68479656 Candida albicans MCH1 NP_010229.1 6320149 Saccharomyces cerevisiae MCH2 NP_012701.2 330443640 Saccharomyces cerevisiae MCH3 NP_014274.1 6324204 Saccharomyces cerevisiae MCH5 NP_014951.2 330443742 Saccharomyces cerevisiae NDT1 NP_012260.1 6322185 Saccharomyces cerevisiae ANI_1_1592184 XP_001401484.2 317038471 Aspergillus niger CaJ7_0216 XP_888808.1 77022728 Candida albicans YALI0E16478g XP_504023.1 50553226 Yarrowia lipolytica KLLA0D14036g XP_453688.1 50307419 Kluyveromyces lactis

Disruption or attenuation of enzymes that synthesize malonyl-CoA and fatty acids can increase the supply of carbon available for fatty alcohol, fatty aldehyde or fatty acid biosynthesis from acetyl-CoA. Exemplary enzymes for disruption or attenuation include fatty acid synthase, acetyl-CoA carboxylase, biotin:apoenzyme ligase, acyl carrier protein, thioesterase, acyltransferases, ACP malonyltransferase, fatty acid elongase, acyl-CoA synthetase, acyl-CoA transferase and acyl-CoA hydrolase.

Another strategy to reduce fatty acid biosynthesis is expression or overexpression of regulatory proteins which repress fatty acid forming genes. Acetyl-CoA carboxylase (EC 6.4.1.2) catalyzes the first step of fatty acid biosynthesis in many organisms: the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. This enzyme utilizes biotin as a cofactor. Exemplary ACC enzymes are encoded by accABCD of E. coli (Davis et al, J Biol Chem 275:28593-8 (2000)), ACCT of Saccharomyces cerevisiae and homologs (Sumper et al, Methods Enzym 71:34-7 (1981)). The mitochondrial acetyl-CoA carboxylase of S. cerevisiae is encoded by HFA1. Acetyl-CoA carboxylase holoenzyme formation requires attachment of biotin by a biotin:apoprotein ligase such as BPL1 of S. cerevisiae.

Protein GenBank ID GI Number Organism ACC1 CAA96294.1 1302498 Saccharomyces cerevisiae KLLA0F06072g XP_455355.1 50310667 Kluyveromyces lactis ACC1 XP_718624.1 68474502 Candida albicans YALI0C11407p XP_501721.1 50548503 Yarrowia lipolytica ANI_1_1724104 XP_001395476.1 145246454 Aspergillus niger accA AAC73296.1 1786382 Escherichia coli accB AAC76287.1 1789653 Escherichia coli accC AAC76288.1 1789654 Escherichia coli accD AAC75376.1 1788655 Escherichia coli HFA1 NP_013934.1 6323863 Saccharomyces cerevisiae BPL1 NP_010140.1 6320060 Saccharomyces cerevisiae

Proteins participating in the synthesis of fatty acids are shown below. The fatty acid synthase enzyme complex of yeast is composed of two multifunctional subunits, FAS1 and FAS2, which together catalyze the net conversion of acetyl-CoA and malonyl-CoA to fatty acids (Lomakin et al, Cell 129: 319-32 (2007)). Additional proteins associated with mitochondrial fatty acid synthesis include OAR1, Mct1, ETR1, ACP1 and PPT2. ACP1 is the mitochondrial acyl carrier protein and PPT2 encodes a phosphopantetheine transferase, which pantetheinylates mitochondrial ACP and is required for fatty acid biosynthesis in the mitochondria (Stuible et al, J Biol Chem: 273: 22334-9 (1998)). A non-genetic strategy for reducing activity of fatty acid synthases is to add an inhibitor such as cerulenin. Global regulators of lipid biosynthesis can also be altered to tune down endogenous fatty acid biosynthesis pathways during production of long chain alcohols or related products. An exemplary global regulator is SNF1 of Yarrowia lipolytica and Saccharomyces cerevisiae.

Protein GenBank ID GI Number Organism FAS1 NP_012739.1 6322666 Saccharomyces cerevisiae FAS2 NP_015093.1 6325025 Saccharomyces cerevisiae FAS1 XP_451653.1 50303423 Kluyveromyces lactis FAS2 XP_452914.1 50305907 Kluyveromyces lactis FAS1 XP_716817.1 68478392 Candida albicans FAS2 XP_723014.1 68465892 Candida albicans FAS1 XP_500912.1 50546885 Yarrowia lipolytica FAS2 XP_501096.1 50547253 Yarrowia lipolytica FAS1 XP_001393490.2 317031809 Aspergillus niger FAS2 XP_001388458.1 145228299 Aspergillus niger OAR1 NP_012868.1 6322795 Saccharomyces cerevisiae MCT1 NP_014864.4 398365823 Saccharomyces cerevisiae ETR1 NP_009582.1 6319500 Saccharomyces cerevisiae ACP1 NP_012729.1 6322656 Saccharomyces cerevisiae PPT2 NP_015177.2 37362701 Saccharomyces cerevisiae SNF1 CAG80498.1 49648180 Yarrowia lipolytica SNF1 P06782.1 134588 Saccharomyces cerevisiae

Disruption or attenuation of elongase enzymes which convert acyl-CoA substrates to longer-chain length fatty acids can also be used to increase fatty alcohol, fatty aldehyde or fatty acid production. Elongase enzymes are found in compartments such as the mitochondria, endoplasmic reticulum, proteoliposomes and peroxisomes. For example, some yeast such as S. cerevisiae are able to synthesize long-chain fatty acids of chain length C16 and higher via a mitochondrial elongase which accepts exogenous or endogenous acyl-CoA substrates (Bessoule et al, FEBS Lett 214: 158-162 (1987)). This system requires ATP for activity. The endoplasmic reticulum also has an elongase system for synthesizing very long chain fatty acids (C18+) from acyl-CoA substrates of varying lengths (Kohlwein et al, Mol Cell Biol 21:109-25 (2001)). Genes involved in this system include TSC13, ELO2 and ELO3. ELO1 catalyzes the elongation of C12 acyl-CoAs to C16-C18 fatty acids.

Protein Accession # GI number Organism ELO2 NP_009963.1 6319882 Saccharomyces cerevisiae ELO3 NP_013476.3 398366027 Saccharomyces cerevisiae TSC13 NP_010269.1 6320189 Saccharomyces cerevisiae ELO1 NP_012339.1 6322265 Saccharomyces cerevisiae

Native enzymes converting acyl-CoA pathway intermediates to acid byproducts can also reduce fatty alcohol, fatty aldehyde or fatty acid yield. For example, CoA hydrolases, transferases and synthetases can act on acyl-CoA intermediates to form short-, medium- or long chain acids. Disruption or attenuation of endogenous CoA hydrolases, CoA transerases and/or reversible CoA synthetases can be used to increase fatty alcohol, fatty aldehyde or fatty acid yield. Exemplary enzymes are shown in the table below.

Protein GenBank ID GI number Organism Tes1 NP_012553.1 6322480 Saccharomyces cerevisiae s288c ACH1 NP_009538.1 6319456 Saccharomyces cerevisiae s288c EHD3 NP_010321.1 6320241 Saccharomyces cerevisiae s288c YALI0F14729p XP_505426.1 50556036 Yarrowia lipolytica YALI0E30965p XP_504613.1 50554409 Yarrowia lipolytica KLLA0E16523g XP_454694.1 50309373 Kluyveromyces lactis KLLA0E10561g XP_454427.1 50308845 Kluyveromyces lactis ACH1 P83773.2 229462795 Candida albicans CaO19.10681 XP_714720.1 68482646 Candida albicans ANI_1_318184 XP_001401512.1 145256774 Aspergillus niger ANI_1_1594124 XP_001401252.2 317035188 Aspergillus niger tesB NP_414986.1 16128437 Escherichia coli tesB NP_355686.2 159185364 Agrobacterium tumefaciens atoA 2492994 P76459.1 Escherichia coli atoD 2492990 P76458.1 Escherichia coli

Enzymes that favor the degradation of products or MI-FAE cycle or termination pathway intermediates can also be disrupted or attenuated. Examples include aldehyde dehydrogenases, aldehyde decarbonylases, oxidative alcohol dehydrogenases, and irreversible fatty acyl-CoA degrading enzymes.

For production of fatty alcohols, fatty aldehydes or fatty acids of the invention, deletion or attenuation of non-specific aldehyde dehydrogenases can improve yield. For production of fatty acids, expression of such an enzyme may improve product formation. Such enzymes can, for example, convert acetyl-CoA into acetaldehyde, fatty aldehydes to fatty acids, or fatty alcohols to fatty acids. Acylating aldehyde dehydrogenase enzymes are described in Example I. Acid-forming aldehyde dehydrogenase are described in Examples III and IX.

The pathway enzymes that favor the reverse direction can also be disrupted or attenuated, if they are detrimental to fatty alcohol, fatty aldehyde or fatty acid production. An example is long chain alcohol dehydrogenases (EC 1.1.1.192) that favor the oxidative direction. Exemplary long chain alcohol dehydrogenases are ADH1 and ADH2 of Geobacillus thermodenitrificans, which oxidize alcohols up to a chain length of C30 (Liu et al, Physiol Biochem 155:2078-85 (2009)). These and other exemplary fatty alcohol dehydrogenase enzymes are listed in Examples I and II. If an alcohol-forming acyl-CoA reductase is utilized for fatty alcohol, fatty aldehyde or fatty acid biosynthesis, deletion of endogenous fatty alcohol dehydrogenases will substantially reduce backflux.

Beta-oxidation enzymes may be reversible and operate in the direction of acyl-CoA synthesis. However, if they are irreversible or strongly favored in the degradation direction they are candidates for disruption or attenuation. An enzyme that fall into this category includes FOX2 of S. cerevisiae, a multifunctional enzyme with 3-hydroxyacyl-CoA dehydrogenase and enoyl-CoA hydratase activity (Hiltunen et al, J Biol Chem 267: 6646-6653 (1992)). Additional genes include degradative thiolases such as POT1 and acyl-CoA dehydrogenases that utilize cofactors other than NAD(P)H (EG. EC 1.3.8.-) such as fadE of E. coli.

Protein GenBank ID GI Number Organism POT1 NP_012106.1 6322031 Saccharomyces cerevisiae FOX2 NP_012934.1 6322861 Saccharomyces cerevisiae fadE AAC73325.2 87081702 Escherichia coli

Fatty acyl-CoA oxidase enzymes such as POX1 of S. cerevisiae catalyze the oxygen-dependent oxidation of fatty acyl-CoA substrates. Enzymes with this activity can be disrupted or attenuated, if they are expressed under fatty alcohol, fatty aldehyde or fatty acid producing conditions. POX1 (EC 1.3.3.6) genes and homologs are shown in the table below. POX1 is subject to regulation by OAF1, which also activates genes involved in peroxisomal beta-oxidation, organization and biogenesis (Luo et al, J Biol Chem 271:12068-75 (1996)). Regulators with functions similar to OAF1, and peroxisomal fatty acid transporters PXA1 and PXA2 are also candidates for deletion.

Protein GenBank ID GI Number Organism POX1 NP_011310.1 6321233 Saccharomyces cerevisiae OAF1 NP_009349.3 330443370 Saccharomyces cerevisiae PXA1 NP_015178.1 6325110 Saccharomyces cerevisiae PXA2 NP_012733.1 6322660 Saccharomyces cerevisiae YALI0F10857g XP_505264.1 50555712 Yarrowia lipolytica YALI0D24750p XP_503244.1 50551539 Yarrowia lipolytica YALI0E32835p XP_504703.1 50554589 Yarrowia lipolytica YALI0E06567p XP_503632.1 50552444 Yarrowia lipolytica YALI0E27654p XP_504475.1 50554133 Yarrowia lipolytica YALI0C23859p XP_502199.1 50549457 Yarrowia lipolytica POX XP_455532.1 50311017 Kluyveromyces lactis POX104 XP_721610.1 68468582 Candida albicans POX105 XP_717995.1 68475844 Candida albicans POX102 XP_721613.1 68468588 Candida albicans

Another candidate for disruption or attenuation is an acyl-CoA binding protein. The acyl binding protein ACB1 of S. cerevisiae, for example, binds acyl-CoA esters and shuttles them to acyl-CoA utilizing processes (Schjerling et al, J Biol Chem 271: 22514-21 (1996)). Deletion of this protein did not impact growth rate and lead to increased accumulation of longer-chain acyl-CoA molecules. Acyl-CoA esters are involved in diverse cellular processes including lipid biosynthesis and homeostatis, signal transduction, growth regulation and cell differentiation (Rose et al, PNAS USA 89: 11287-11291 (1992)).

Protein GenBank ID GI Number Organism ACB1 P31787.3 398991 Saccharomyces cerevisiae KLLA0B05643g XP_451787.2 302309983 Kluyveromyces lactis YALI0E23185g XP_002143080.1 210076210 Yarrowia lipolytica ANI_1_1084034 XP_001390082.1 145234867 Aspergillus niger To achieve high yields of fatty alcohols, fatty aldehydes or fatty acids, it is desirable that the host organism can supply the cofactors required by the MI-FAE cycle and/or the termination pathway in sufficient quantities. In several organisms, in particular eukaryotic organisms, such as several Saccharomyces, Kluyveromyces, Candida, Aspergillus, and Yarrowia species, NADH is more abundant than NADPH in the cytosol as it is produced in large quantities by glycolysis. NADH can be made even more abundant by converting pyruvate to acetyl-CoA by means of heterologous or native NAD-dependant enzymes such as NAD-dependant pyruvate dehydrogenase, NAD-dependant formate dehydrogenase, NADH:ferredoxin oxidoreductase, or NAD-dependant acylating acetylaldehyde dehydrogenase in the cytosol. Given the abundance of NADH in the cytosol of most organisms, it can be beneficial for all reduction steps of the MI-FAE cycle and/or termination pathway to accept NADH as the reducing agent preferentially over other reducing agents such as NADPH. High yields of fatty alcohols, fatty aldehydes or fatty acids can thus be accomplished by, for example: 1) identifying and implementing endogenous or exogenous MI-FAE cycle and/or termination pathway enzymes with a stronger preference for NADH than other reducing equivalents such as NADPH; 2) attenuating one or more endogenous MI-FAE cycle or termination pathway enzymes that contribute NADPH-dependant reduction activity; 3) altering the cofactor specificity of endogenous or exogenous MI-FAE cycle or termination pathway enzymes so that they have a stronger preference for NADH than their natural versions; or 4) altering the cofactor specificity of endogenous or exogenous MI-FAE cycle or termination pathway enzymes so that they have a weaker preference for NADPH than their natural versions.

Strategies for engineering NADH-favoring MI-FAE cycle and/or termination pathways are described in further detail in Example V. Methods for changing the cofactor specificity of an enzyme are well known in the art, and an example is described in Example VI.

If one or more of the MI-FAE cycle and/or termination pathway enzymes utilizes NADPH as the cofactor, it can be beneficial to increase the production of NADPH in the host organism. In particular, if the MI-FAE cycle and/or termination pathway is present in the cytosol of the host organism, methods for increasing NADPH production in the cytosol can be beneficial. Several approaches for increasing cytosolic production of NADPH can be implemented including channeling an increased amount of flux through the oxidative branch of the pentose phosphate pathway relative to wild-type, channeling an increased amount of flux through the Entner Doudoroff pathway relative to wild-type, introducing a soluble or membrane-bound transhydrogenase to convert NADH to NADPH, or employing NADP-dependant versions of the following enzymes: phosphorylating or non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase, pyruvate dehydrogenase, formate dehydrogenase, or acylating acetylaldehyde dehydrogenase. These activities can be augmented by disrupting or attenuating native NAD-dependant enzymes including glyceraldehyde-3-phosphate dehydrogenase, pyruvate dehydrogenase, formate dehydrogenase, or acylating acetylaldehyde dehydrogenase. Strategies for engineering increased NADPH availability are described in Example VII.

Synthesis of fatty alcohols, fatty aldehyes or fatty acids in the cytosol can be dependent upon the availability of sufficient carbon and reducing equivalents. Therefore, without being bound to any particular theory of operation, increasing the redox ratio of NAD(P)H to NAD(P) can help drive the MI-FAE cycle and/or termination pathway in the forward direction. Methods for increasing the redox ratio of NAD(P)H to NAD(P) include limiting respiration, attenuating or disrupting competing pathways that produce reduced byproducts such as ethanol and glycerol, attenuating or eliminating the use of NADH by NADH dehydrogenases, and attenuating or eliminating redox shuttles between compartments.

One exemplary method to provide an increased number of reducing equivalents, such as NAD(P)H, for enabling the formation of fatty alcohols, fatty aldehydes or fatty acids is to constrain the use of such reducing equivalents during respiration. Respiration can be limited by: reducing the availability of oxygen, attenuating NADH dehydrogenases and/or cytochrome oxidase activity, attenuating G3P dehydrogenase, and/or providing excess glucose to Crabtree positive organisms.

Restricting oxygen availability by culturing the non-naturally occurring eukaryotic organisms in a fermenter is one example for limiting respiration and thereby increasing the ratio of NAD(P)H to NAD(P). The ratio of NAD(P)H/NAD(P) increases as culture conditions become more anaerobic, with completely anaerobic conditions providing the highest ratios of the reduced cofactors to the oxidized ones. For example, it has been reported that the ratio of NADH/NAD=0.02 in aerobic conditions and 0.75 in anaerobic conditions in E. coli (de Graes et al, J Bacteriol 181:2351-57 (1999)).

Respiration can also be limited by reducing expression or activity of NADH dehydrogenases and/or cytochrome oxidases in the cell under aerobic conditions. In this case, respiration can be limited by the capacity of the electron transport chain. Such an approach has been used to enable anaerobic metabolism of E. coli under completely aerobic conditions (Portnoy et al, AEM 74:7561-9 (2008)). S. cerevisiae can oxidize cytosolic NADH directly using external NADH dehydrogenases, encoded by NDE1 and NDE2. One such NADH dehydrogenase in Yarrowia lipolytica is encoded by NDH2 (Kerscher et al, J Cell Sci 112:2347-54 (1999)). These and other NADH dehydrogenase enzymes are listed in the table below.

Protein GenBank ID GI number Organism NDE1 NP_013865.1 6323794 Saccharomyces cerevisiae s288c NDE2 NP_010198.1 6320118 Saccharomyces cerevisiae s288c NDH2 AJ006852.1 3718004 Yarrowia lipolytica ANI_1_610074 XP_001392541.2 317030427 Aspergillus niger ANI_1_2462094 XP_001394893.2 317033119 Aspergillus niger KLLA0E21891g XP_454942.1 50309857 Kluyveromyces lactis KLLA0C06336g XP_452480.1 50305045 Kluyveromyces lactis NDE1 XP_720034.1 68471982 Candida albicans NDE2 XP_717986.1 68475826 Candida albicans

Cytochrome oxidases of Saccharomyces cerevisiae include the COX gene products. COX1-3 are the three core subunits encoded by the mitochondrial genome, whereas COX4-13 are encoded by nuclear genes. Attenuation or disruption of any of the cytochrome genes results in a decrease or block in respiratory growth (Hermann and Funes, Gene 354:43-52 (2005)). Cytochrome oxidase genes in other organisms can be inferred by sequence homology.

Protein GenBank ID GI number Organism COX1 CAA09824.1 4160366 Saccharomyces cerevisiae s288c COX2 CAA09845.1 4160387 Saccharomyces cerevisiae s288c COX3 CAA09846.1 4160389 Saccharomyces cerevisiae s288c COX4 NP_011328.1 6321251 Saccharomyces cerevisiae s288c COX5A NP_014346.1 6324276 Saccharomyces cerevisiae s288c COX5B NP_012155.1 6322080 Saccharomyces cerevisiae s288c COX6 NP_011918.1 6321842 Saccharomyces cerevisiae s288c COX7 NP_013983.1 6323912 Saccharomyces cerevisiae s288c COX8 NP_013499.1 6323427 Saccharomyces cerevisiae s288c COX9 NP_010216.1 6320136 Saccharomyces cerevisiae s288c COX12 NP_013139.1 6323067 Saccharomyces cerevisiae s288c COX13 NP_011324.1 6321247 Saccharomyces cerevisiae s288c

Cytosolic NADH can also be oxidized by the respiratory chain via the G3P dehydrogenase shuttle, consisting of cytosolic NADH-linked G3P dehydrogenase and a membrane-bound G3P:ubiquinone oxidoreductase. The deletion or attenuation of G3P dehydrogenase enzymes will also prevent the oxidation of NADH for respiration. Enzyme candidates encoding these enzymes are described herein.

Additionally, in Crabtree positive organisms, fermentative metabolism can be achieved in the presence of excess of glucose. For example, S. cerevisiae makes ethanol even under aerobic conditions. The formation of ethanol and glycerol can be reduced/eliminated and replaced by the production of fatty alcohol, fatty aldehyde or fatty acid in a Crabtree positive organism by feeding excess glucose to the Crabtree positive organism. In another aspect, provided herein is a method for producing fatty alcohols, fatty aldehydes or fatty acids, comprising culturing a non-naturally occurring eukaryotic organism under conditions and for a sufficient period of time to produce fatty alcohol, fatty aldehyde or fatty acid, wherein the eukaryotic organism is a Crabtree positive organism that comprises at least one exogenous nucleic acid encoding a MI-FAE cycle and/or termination pathway enzyme and wherein eukaryotic organism is in a culture medium comprising excess glucose.

Preventing formation of reduced fermentation byproducts will increase the availability of both carbon and reducing equivalents for fatty alcohol, fatty aldehyde or fatty acid production. The two key reduced byproducts under anaerobic and microaerobic conditions are ethanol and glycerol. Ethanol is typically formed from pyruvate in two enzymatic steps catalyzed by pyruvate decarboxylase and ethanol dehydrogenase. Glycerol is formed from the glycolytic intermediate dihydroxyacetone phosphate by the enzymes glycerol-3-phosphate dehydrogenase and glycerol-3-phosphate phosphatase. Attenuation of one or more of these enzyme activities will increase the yield of fatty alcohols, fatty aldehydes or fatty acids. Strain engineering strategies for reducing or eliminating ethanol and glycerol formation are described herein.

Yeast such as S. cerevisiae can produce glycerol to allow for regeneration of NAD(P) under anaerobic conditions. Another way to reduce or eliminate glycerol production is by oxygen-limited cultivation (Bakker et al, supra). Glycerol formation only sets in when the specific oxygen uptake rates of the cells decrease below the rate that is required to reoxidize the NADH formed in biosynthesis.

In addition to the redox sinks listed above, malate dehydrogenase can potentially draw away reducing equivalents when it functions in the reductive direction. Several redox shuttles believed to be functional in S. cerevisiae utilize this enzyme to transfer reducing equivalents between the cytosol and the mitochondria. This transfer of redox can be prevented by attenuating malate dehydrogenase and/or malic enzyme activity. The redox shuttles that can be blocked by the attenuation of mdh include (i) malate-asparate shuttle, (ii) malate-oxaloacetate shuttle, and (iii) malate-pyruvate shuttle. Genes encoding malate dehydrogenase and malic enzymes are listed in the table below.

Protein GenBank ID GI Number Organism MDH1 NP_012838.1 6322765 Saccharomyces cerevisiae MDH2 NP_014515.2 116006499 Saccharomyces cerevisiae MDH3 NP_010205.1 6320125 Saccharomyces cerevisiae MAE1 NP_012896.1 6322823 Saccharomyces cerevisiae MDH1 XP_722674.1 68466384 Candida albicans MDH2 XP_718638.1 68474530 Candida albicans MAE1 XP_716669.1 68478574 Candida albicans KLLA0F25960g XP_456236.1 50312405 Kluyveromyces lactis KLLA0E18635g XP_454793.1 50309563 Kluyveromyces lactis KLLA0E07525g XP_454288.1 50308571 Kluyveromyces lactis YALI0D16753p XP_502909.1 50550873 Yarrowia lipolytica YALI0E18634p XP_504112.1 50553402 Yarrowia lipolytica ANI_1_268064 XP_001391302.1 145237310 Aspergillus niger ANI_1_12134 XP_001396546.1 145250065 Aspergillus niger ANI_1_22104 XP_001395105.2 317033225 Aspergillus niger

Overall, disruption or attenuation of the aforementioned sinks for redox either individually or in combination with the other redox sinks can eliminate or lower the use of reducing power for respiration or byproduct formation. It has been reported that the deletion of the external NADH dehydrogenases (NDE1 and NDE2) and the mitochondrial G3P dehydrogenase (GUT2) almost completely eliminates cytosolic NAD+ regeneration in S. cerevisiae (Overkamp et al, J Bacteriol 182:2823-30 (2000)).

Microorganisms of the invention produce fatty alcohols, fatty aldehydes or fatty acids and optionally secrete the fatty alcohols, fatty aldehydes or fatty acids into the culture medium. S. cerevisiae, Yarrowia lipolytica and E. coli harboring heterologous fatty alcohol forming activities accumulated fatty alcohols intracellularly; however fatty alcohols were not detected in the culture medium (Behrouzian et al, United States Patent Application 20100298612). The introduction of fatty acyl-CoA reductase enzymes with improved activity resulted in higher levels of fatty alcohol secreted into the culture media. Alternately, introduction of a fatty alcohol, fatty aldehyde or fatty acid transporter or transport system can improve extracellular accumulation of fatty alcohols, fatty aldehydes or fatty acids. Exemplary transporters are listed in the table below.

GI Protein GenBank ID Number Organism Fatp NP_524723.2 24583463 Drosophila melanogaster AY161280.1:45 . . . 1757 AAN73268.1 34776949 Rhodococcus erythropolis acrA CAF23274.1 46399825 Candidatus Protochlamydia amoebophila acrB CAF23275.1 46399826 Candidatus Protochlamydia amoebophila CER5 AY734542.1 52354013 Arabidopsis thaliana AmiS2 JC5491 7449112 Rhodococcus sp. ANI_1_1160064 XP_001391993.1 145238692 Aspergillus niger YALI0E16016g XP_504004.1 50553188 Yarrowia lipolytica

Thus, in some embodiments, the invention provides a non-naturally occurring microbial organism as disclosed herein having one or more gene disruptions, wherein the one or more gene disruptions occur in endogenous genes encoding proteins or enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by the microbial organism, the one or more gene disruptions confer increased production of a fatty alcohol, fatty aldehyde or fatty acid in the microbial organism. Accordingly, the protein or enzyme can be a fatty acid synthase, an acetyl-CoA carboxylase, a biotin:apoenzyme ligase, an acyl carrier protein, a thioesterase, an acyltransferase, an ACP malonyltransferase, a fatty acid elongase, an acyl-CoA synthetase, an acyl-CoA transferase, an acyl-CoA hydrolase, a pyruvate decarboxylase, a lactate dehydrogenase, an alcohol dehydrogenase, an acid-forming aldehyde dehydrogenases, an acetate kinase, a phosphotransacetylase, a pyruvate oxidase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate phosphatase, a mitochondrial pyruvate carrier, a peroxisomal fatty acid transporter, a peroxisomal acyl-CoA transporter, a peroxisomal carnitine/acylcarnitine transferase, an acyl-CoA oxidase, or an acyl-CoA binding protein. In some aspects, the one or more gene disruptions include a deletion of the one or more genes.

In some embodiments, the invention provides a non-naturally occurring microbial organism as described herein, wherein one or more enzymes of the MI-FAE cycle or the termination pathway preferentially react with an NADH cofactor or have reduced preference for reacting with an NAD(P)H cofactor. For example, the one or more enzymes of the MI-FAE cycle can be a 3-ketoacyl-CoA reductase or an enoyl-CoA reductase. For the termination pathway, the one or more enzymes can be an acyl-CoA reductase (aldehyde forming), an alcohol dehydrogenase, an acyl-CoA reductase (alcohol forming), an aldehyde decarbonylase, an acyl-ACP reductase, an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase.

In some embodiments, the invention provides a non-naturally occurring microbial organism as described herein having one or more gene disruptions in genes encoding proteins or enzymes that result in an increased ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism following the disruptions. Accordingly, the gene encoding a protein or enzyme that results in an increased ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism following the disruptions can be an NADH dehydrogenase, a cytochrome oxidase, a G3P dehydrogenase, G3P phosphatase, an alcohol dehydrogenase, a pyruvate decarboxylase, an aldehyde dehydrogenase (acid forming), a lactate dehydrogenase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate: quinone oxidoreductase, a malic enzyme and a malate dehydrogenase. In some aspects, the one or more gene disruptions include a deletion of the one or more genes.

In some embodiments, the non-naturally occurring microbial organism of the invention is Crabtree positive and is in culture medium comprising excess glucose. In such conditions, as described herein, the microbial organism can result in increasing the ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism.

In some embodiments, the invention provides a non-naturally occurring microbial organism as described herein having at least one exogenous nucleic acid encoding an extracellular transporter or an extracellular transport system for a fatty alcohol, fatty aldehyde or fatty acid of the invention.

In some embodiments, the invention provides a non-naturally occurring microbial organism as described herein, wherein one or more endogenous enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by said microbial organism, has attenuated enzyme activity or expression levels. Accordingly, the endogenous enzyme can be a fatty acid synthase, an acetyl-CoA carboxylase, a biotin:apoenzyme ligase, an acyl carrier protein, a thioesterase, an acyltransferase, an ACP malonyltransferase, a fatty acid elongase, an acyl-CoA synthetase, an acyl-CoA transferase, an acyl-CoA hydrolase, a pyruvate decarboxylase, a lactate dehydrogenase, an alcohol dehydrogenase, an acid-forming aldehyde dehydrogenases, an acetate kinase, a phosphotransacetylase, a pyruvate oxidase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate phosphatase, a mitochondrial pyruvate carrier, a peroxisomal fatty acid transporter, a peroxisomal acyl-CoA transporter, a peroxisomal carnitine/acylcarnitine transferase, an acyl-CoA oxidase, or an acyl-CoA binding protein.

In some embodiments, the invention provides a non-naturally occurring microbial organism as described herein, wherein one or more endogenous enzymes involved in the oxidation of NAD(P)H or NADH, has attenuated enzyme activity or expression levels. Accordingly, the one or more endogenous enzymes can be a NADH dehydrogenase, a cytochrome oxidase, a G3P dehydrogenase, G3P phosphatase, an alcohol dehydrogenase, a pyruvate decarboxylase, an aldehyde dehydrogenase (acid forming), a lactate dehydrogenase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate:quinone oxidoreductase, a malic enzyme and a malate dehydrogenase.

The non-naturally occurring microbal organisms of the invention can contain stable genetic alterations, which refers to microorganisms that can be cultured for greater than five generations without loss of the alteration. Generally, stable genetic alterations include modifications that persist greater than 10 generations, particularly stable modifications will persist more than about 25 generations, and more particularly, stable genetic modifications will be greater than 50 generations, including indefinitely.

In the case of gene disruptions, a particularly useful stable genetic alteration is a gene deletion. The use of a gene deletion to introduce a stable genetic alteration is particularly useful to reduce the likelihood of a reversion to a phenotype prior to the genetic alteration. For example, stable growth-coupled production of a biochemical can be achieved, for example, by deletion of a gene encoding an enzyme catalyzing one or more reactions within a set of metabolic modifications. The stability of growth-coupled production of a biochemical can be further enhanced through multiple deletions, significantly reducing the likelihood of multiple compensatory reversions occurring for each disrupted activity.

Also provided is a method of producing a non-naturally occurring microbial organisms having stable growth-coupled production of fatty alcohol, fatty aldehyde or fatty acid. The method can include identifying in silico a set of metabolic modifications that increase production of fatty alcohol, fatty aldehyde or fatty acid, for example, increase production during exponential growth; genetically modifying an organism to contain the set of metabolic modifications that increase production of fatty alcohol, fatty aldehyde or fatty acid, and culturing the genetically modified organism. If desired, culturing can include adaptively evolving the genetically modified organism under conditions requiring production of fatty alcohol, fatty aldehyde or fatty acid. The methods of the invention are applicable to bacterium, yeast and fungus as well as a variety of other cells and microorganism, as disclosed herein.

Thus, the invention provides a non-naturally occurring microbial organism comprising one or more gene disruptions that confer increased production of fatty alcohol, fatty aldehyde or fatty acid. In one embodiment, the one or more gene disruptions confer growth-coupled production of fatty alcohol, fatty aldehyde or fatty acid, and can, for example, confer stable growth-coupled production of fatty alcohol, fatty aldehyde or fatty acid. In another embodiment, the one or more gene disruptions can confer obligatory coupling of fatty alcohol, fatty aldehyde or fatty acid production to growth of the microbial organism. Such one or more gene disruptions reduce the activity of the respective one or more encoded enzymes.

The non-naturally occurring microbial organism can have one or more gene disruptions included in a gene encoding a enzyme or protein disclosed herein. As disclosed herein, the one or more gene disruptions can be a deletion. Such non-naturally occurring microbial organisms of the invention include bacteria, yeast, fungus, or any of a variety of other microorganisms applicable to fermentation processes, as disclosed herein.

Thus, the invention provides a non-naturally occurring microbial organism, comprising one or more gene disruptions, where the one or more gene disruptions occur in genes encoding proteins or enzymes where the one or more gene disruptions confer increased production of fatty alcohol, fatty aldehyde or fatty acid in the organism. The production of fatty alcohol, fatty aldehyde or fatty acid can be growth-coupled or not growth-coupled. In a particular embodiment, the production of fatty alcohol, fatty aldehyde or fatty acid can be obligatorily coupled to growth of the organism, as disclosed herein.

The invention provides non naturally occurring microbial organisms having genetic alterations such as gene disruptions that increase production of fatty alcohol, fatty aldehyde or fatty acid, for example, growth-coupled production of fatty alcohol, fatty aldehyde or fatty acid. Product production can be, for example, obligatorily linked to the exponential growth phase of the microorganism by genetically altering the metabolic pathways of the cell, as disclosed herein. The genetic alterations can increase the production of the desired product or even make the desired product an obligatory product during the growth phase. Metabolic alterations or transformations that result in increased production and elevated levels of fatty alcohol, fatty aldehyde or fatty acid biosynthesis are exemplified herein. Each alteration corresponds to the requisite metabolic reaction that should be functionally disrupted. Functional disruption of all reactions within one or more of the pathways can result in the increased production of fatty alcohol, fatty aldehyde or fatty acid by the engineered strain during the growth phase.

Each of these non-naturally occurring alterations result in increased production and an enhanced level of fatty alcohol, fatty aldehyde or fatty acid production, for example, during the exponential growth phase of the microbial organism, compared to a strain that does not contain such metabolic alterations, under appropriate culture conditions. Appropriate conditions include, for example, those disclosed herein, including conditions such as particular carbon sources or reactant availabilities and/or adaptive evolution.

Given the teachings and guidance provided herein, those skilled in the art will understand that to introduce a metabolic alteration such as attenuation of an enzyme, it can be necessary to disrupt the catalytic activity of the one or more enzymes involved in the reaction. Alternatively, a metabolic alteration can include disrupting expression of a regulatory protein or cofactor necessary for enzyme activity or maximal activity. Furthermore, genetic loss of a cofactor necessary for an enzymatic reaction can also have the same effect as a disruption of the gene encoding the enzyme. Disruption can occur by a variety of methods including, for example, deletion of an encoding gene or incorporation of a genetic alteration in one or more of the encoding gene sequences. The encoding genes targeted for disruption can be one, some, or all of the genes encoding enzymes involved in the catalytic activity. For example, where a single enzyme is involved in a targeted catalytic activity, disruption can occur by a genetic alteration that reduces or eliminates the catalytic activity of the encoded gene product. Similarly, where the single enzyme is multimeric, including heteromeric, disruption can occur by a genetic alteration that reduces or destroys the function of one or all subunits of the encoded gene products. Destruction of activity can be accomplished by loss of the binding activity of one or more subunits required to form an active complex, by destruction of the catalytic subunit of the multimeric complex or by both. Other functions of multimeric protein association and activity also can be targeted in order to disrupt a metabolic reaction of the invention. Such other functions are well known to those skilled in the art. Similarly, a target enzyme activity can be reduced or eliminated by disrupting expression of a protein or enzyme that modifies and/or activates the target enzyme, for example, a molecule required to convert an apoenzyme to a holoenzyme. Further, some or all of the functions of a single polypeptide or multimeric complex can be disrupted according to the invention in order to reduce or abolish the catalytic activity of one or more enzymes involved in a reaction or metabolic modification of the invention. Similarly, some or all of enzymes involved in a reaction or metabolic modification of the invention can be disrupted so long as the targeted reaction is reduced or eliminated.

Given the teachings and guidance provided herein, those skilled in the art also will understand that an enzymatic reaction can be disrupted by reducing or eliminating reactions encoded by a common gene and/or by one or more orthologs of that gene exhibiting similar or substantially the same activity. Reduction of both the common gene and all orthologs can lead to complete abolishment of any catalytic activity of a targeted reaction. However, disruption of either the common gene or one or more orthologs can lead to a reduction in the catalytic activity of the targeted reaction sufficient to promote coupling of growth to product biosynthesis. Exemplified herein are both the common genes encoding catalytic activities for a variety of metabolic modifications as well as their orthologs. Those skilled in the art will understand that disruption of some or all of the genes encoding a enzyme of a targeted metabolic reaction can be practiced in the methods of the invention and incorporated into the non-naturally occurring microbial organisms of the invention in order to achieve the increased production of fatty alcohol, fatty aldehyde or fatty acid or growth-coupled product production.

Given the teachings and guidance provided herein, those skilled in the art also will understand that enzymatic activity or expression can be attenuated using well known methods. Reduction of the activity or amount of an enzyme can mimic complete disruption if the reduction causes activity of the enzyme to fall below a critical level that is normally required for the pathway to function. Reduction of enzymatic activity by various techniques rather than disruption can be important for an organism's viability. Methods of reducing enzymatic activity that result in similar or identical effects of a gene disruption include, but are not limited to: reducing gene transcription or translation; destabilizing mRNA, protein or catalytic RNA; and mutating a gene that affects enzyme kinetics. Natural or imposed regulatory controls can also accomplish enzyme attenuation including: promoter replacement; loss or alteration of transcription factors; introduction of inhibitory RNAs or peptides such as siRNA, antisense RNA, RNA or peptide/small-molecule binding aptamers, ribozymes, aptazymes and riboswitches; and addition of drugs and other chemicals that reduce or disrupt enzymatic activity such as gene splicing.

One of ordinary skill in the art will also recognize that attenuation of an enzyme can be done at various levels. For example, at the gene level, mutations causing a partial or complete null phenotype or epistatic genetic effects that mask the activity of a gene product can be used to attenuate an enzyme. At the gene expression level, methods for attenuation include: coupling transcription to an endogenous or exogenous inducer such as IPTG, then adding low or 0 levels of inducer during the production phase; introducing or modifying positive or negative regulators; modify histone acetylation/deacetylation in region where gene is integrated; introducing a transposition to disrupt a promoter or a regulatory gene; flipping of a transposable element or promoter region; deleting one allele resulting in loss of heterozygosity in a diploid organism; introducing nucleic acids that increase RNA degradation; or in bacteria, for example, introduction of a tmRNA tag, which can lead to RNA degradation and ribosomal stalling. At the translational level, attenuation can include: introducing rare codons to limit translation; introducing RNA interference molecules that block translation; modifying regions outside the coding sequence, such as introducing secondary structure into UTR regions to block translation or reduce efficiency of translation; adding RNAase sites for rapid transcript degradation; introducing antisense RNA oligomers or antisense transcripts; introducing RNA or peptide aptamers, ribozymes, aptazymes, riboswitches; or introducing translational regulatory elements involving RNA structure that can prevent or reduce translation that can be controlled by the presence or absence of small molecules. At the level of enzyme localization and/or longevity, enzyme attenuation can include: adding a degradation tag for faster protein turnover; or adding a localization tag that results in the enzyme being localized to a compartment where it would not be able to react normally. At the level of post-translational regulation, enzyme attenuation can include: increasing intracellular concentration of known inhibitors; or modifying post-translational modified sites. At the level of enzyme activity, enzyme attenuation can include: adding endogenous or exogenous inhibitor, such as a target-specific drug, to reduce enzyme activity; limiting availability of essential cofactors, such as B 12, for an enzyme that require it; chelating a metal ion that is required for activity; or introducing a dominant negative mutation.

In some embodiments, microaerobic designs can be used based on the growth-coupled formation of the desired product. To examine this, production cones can be constructed for each strategy by first maximizing and, subsequently minimizing the product yields at different rates of biomass formation feasible in the network. If the rightmost boundary of all possible phenotypes of the mutant network is a single point, it implies that there is a unique optimum yield of the product at the maximum biomass formation rate possible in the network. In other cases, the rightmost boundary of the feasible phenotypes is a vertical line, indicating that at the point of maximum biomass the network can make any amount of the product in the calculated range, including the lowest amount at the bottommost point of the vertical line. Such designs are given a low priority.

The fatty alcohol, fatty aldehyde or fatty acid-production strategies identified in the various tables disclosed herein can be disrupted to increase production of fatty alcohol, fatty aldehyde or fatty acid. Accordingly, the invention also provides a non-naturally occurring microbial organism having metabolic modifications coupling fatty alcohol, fatty aldehyde or fatty acid production to growth of the organism, where the metabolic modifications includes disruption of one or more genes selected from the genes encoding proteins and/or enzymes shown in the various tables disclosed herein.

Each of the strains can be supplemented with additional deletions if it is determined that the strain designs do not sufficiently increase the production of fatty alcohol, fatty aldehyde or fatty acid and/or couple the formation of the product with biomass formation. Alternatively, some other enzymes not known to possess significant activity under the growth conditions can become active due to adaptive evolution or random mutagenesis. Such activities can also be knocked out. However, the list of gene deletion disclosed herein allows the construction of strains exhibiting high-yield production of fatty alcohol, fatty aldehyde or fatty acid, including growth-coupled production of fatty alcohol, fatty aldehyde or fatty acid.

In some embodiments, the invention provides a method for producing a compound of Formula (I):

wherein R₁ is C₁₋₂₄ linear alkyl; R₂ is CH₂OH, CHO, or COOH; R₃ is H, OH, or oxo (═O); and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four, comprising culturing a non-naturally occurring microbial organism described herein under conditions and for a sufficient period of time to produce the compound of Formula (I), wherein the non-naturally occurring microbial organism has one or more gene disruptions, wherein the one or more gene disruptions occur in endogenous genes encoding proteins or enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by the microbial organism, the one or more gene disruptions confer increased production of a fatty alcohol, fatty aldehyde or fatty acid in the microbial organism. Accordingly, the protein or enzyme can be a fatty acid synthase, an acetyl-CoA carboxylase, a biotin:apoenzyme ligase, an acyl carrier protein, a thioesterase, an acyltransferases, an ACP malonyltransferase, a fatty acid elongase, an acyl-CoA synthetase, an acyl-CoA transferase, an acyl-CoA hydrolase, a pyruvate decarboxylase, a lactate dehydrogenase, an alcohol dehydrogenase, an acid-forming aldehyde dehydrogenases, an acetate kinase, a phosphotransacetylase, a pyruvate oxidase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate phosphatase, a mitochondrial pyruvate carrier, a peroxisomal fatty acid transporters, a peroxisomal acyl-CoA transporters, a peroxisomal carnitine/acylcarnitine transferases, an acyl-CoA oxidase, or an acyl-CoA binding protein. In some aspects, the one or more gene disruptions include a deletion of the one or more genes.

In some embodiments, the invention provides a method for producing a fatty alcohol, fatty aldehyde or fatty acid using a non-naturally occurring microbial organism as described herein, wherein one or more enzymes of the MI-FAE cycle or the termination pathway preferentially react with an NADH cofactor or have reduced preference for reacting with an NAD(P)H cofactor. For example, the one or more enzymes of the MI-FAE cycle can be a 3-ketoacyl-CoA reductase or an enoyl-CoA reductase. For the termination pathway, the one or more enzymes can be an acyl-CoA reductase (aldehyde forming), an alcohol dehydrogenase, an acyl-CoA reductase (alcohol forming), an aldehyde decarbonylase, an acyl-ACP reductase, an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase.

In some embodiments, the invention provides a method for producing a fatty alcohol, fatty aldehyde or fatty acid using a non-naturally occurring microbial organism as described herein having one or more gene disruptions in genes encoding proteins or enzymes that result in an increased ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism following the disruptions. Accordingly, the gene encoding a protein or enzyme that results in an increased ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism following the disruptions can be an NADH dehydrogenase, a cytochrome oxidase, a glycerol-3-phosphate (G3P) dehydrogenase, a glycerol-3-phosphate (G3P) phosphatase, an alcohol dehydrogenase, a pyruvate decarboxylase, an aldehyde dehydrogenase (acid forming), a lactate dehydrogenase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate: quinone oxidoreductase, a malic enzyme and a malate dehydrogenase. In some aspects, the one or more gene disruptions include a deletion of the one or more genes.

In some embodiments, the invention provides a method for producing a fatty alcohol, fatty aldehyde or fatty acid using a non-naturally occurring microbial organism of the invention that is Crabtree positive and is in culture medium comprising excess glucose. In such conditions, as described herein, the microbial organism can result in increasing the ratio of NAD(P)H to NAD(P) present in the cytosol of the microbial organism.

In some embodiments, the invention provides a method for producing a fatty alcohol, fatty aldehyde or fatty acid using a non-naturally occurring microbial organism as described herein having at least one exogenous nucleic acid encoding an extracellular transporter or an extracellular transport system for a fatty alcohol, fatty aldehyde or fatty acid of the invention.

In some embodiments, the invention provides a method for producing a fatty alcohol, fatty aldehyde or fatty acid using a non-naturally occurring microbial organism as described herein, wherein one or more endogenous enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by said microbial organism, has attenuated enzyme activity or expression levels. Accordingly, the endogenous enzyme can be a fatty acid synthase, an acetyl-CoA carboxylase, a biotin:apoenzyme ligase, an acyl carrier protein, a thioesterase, an acyltransferase, an ACP malonyltransferase, a fatty acid elongase, an acyl-CoA synthetase, an acyl-CoA transferase, an acyl-CoA hydrolase, a pyruvate decarboxylase, a lactate dehydrogenase, an alcohol dehydrogenase, an acid-forming aldehyde dehydrogenases, an acetate kinase, a phosphotransacetylase, a pyruvate oxidase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate phosphatase, a mitochondrial pyruvate carrier, a peroxisomal fatty acid transporter, a peroxisomal acyl-CoA transporter, a peroxisomal carnitine/acylcarnitine transferase, an acyl-CoA oxidase, and an acyl-CoA binding protein.

In some embodiments, the invention provides a method for producing a fatty alcohol, fatty aldehyde or fatty acid using a non-naturally occurring microbial organism as described herein, wherein one or more endogenous enzymes involved in the oxidation of NAD(P)H or NADH, has attenuated enzyme activity or expression levels. Accordingly, the one or more endogenous enzymes can be NADH dehydrogenase, a cytochrome oxidase, a glycerol-3-phosphate dehydrogenase, glycerol-3-phosphate phosphatase, an alcohol dehydrogenase, a pyruvate decarboxylase, an aldehyde dehydrogenase (acid forming), a lactate dehydrogenase, a glycerol-3-phosphate dehydrogenase, a glycerol-3-phosphate:quinone oxidoreductase, a malic enzyme and a malate dehydrogenase.

A fatty alcohol, fatty aldehyde or fatty acid can be harvested or isolated at any time point during the culturing of the microbial organism, for example, in a continuous and/or near-continuous culture period, as disclosed herein. Generally, the longer the microorganisms are maintained in a continuous and/or near-continuous growth phase, the proportionally greater amount of fatty alcohol, fatty aldehyde or fatty acid can be produced.

Therefore, the invention additionally provides a method for producing fatty alcohol, fatty aldehyde or fatty acid that includes culturing a non-naturally occurring microbial organism having one or more gene disruptions, as disclosed herein. The disruptions can occur in one or more genes encoding an enzyme that increases production of fatty alcohol, fatty aldehyde or fatty acid, including optionally coupling fatty alcohol, fatty aldehyde or fatty acid production to growth of the microorganism when the gene disruption reduces or eliminates an activity of the enzyme. For example, the disruptions can confer stable growth-coupled production of fatty alcohol, fatty aldehyde or fatty acid onto the non-naturally microbial organism.

In some embodiments, the gene disruption can include a complete gene deletion. In some embodiments other methods to disrupt a gene include, for example, frameshifting by omission or addition of oligonucleotides or by mutations that render the gene inoperable. One skilled in the art will recognize the advantages of gene deletions, however, because of the stability it confers to the non-naturally occurring organism from reverting to a parental phenotype in which the gene disruption has not occurred. In particular, the gene disruptions are selected from the gene sets as disclosed herein.

Once computational predictions are made of gene sets for disruption to increase production of fatty alcohol, fatty aldehyde or fatty acid, the strains can be constructed, evolved, and tested. Gene disruptions, including gene deletions, are introduced into host organism by methods well known in the art. A particularly useful method for gene disruption is by homologous recombination, as disclosed herein.

The engineered strains can be characterized by measuring the growth rate, the substrate uptake rate, and/or the product/byproduct secretion rate. Cultures can be grown and used as inoculum for a fresh batch culture for which measurements are taken during exponential growth. The growth rate can be determined by measuring optical density using a spectrophotometer (A600). Concentrations of glucose and other organic acid byproducts in the culture supernatant can be determined by well known methods such as HPLC, GC-MS or other well known analytical methods suitable for the analysis of the desired product, as disclosed herein, and used to calculate uptake and secretion rates.

Strains containing gene disruptions can exhibit suboptimal growth rates until their metabolic networks have adjusted to their missing functionalities. To assist in this adjustment, the strains can be adaptively evolved. By subjecting the strains to adaptive evolution, cellular growth rate becomes the primary selection pressure and the mutant cells are compelled to reallocate their metabolic fluxes in order to enhance their rates of growth. This reprogramming of metabolism has been recently demonstrated for several E. coli mutants that had been adaptively evolved on various substrates to reach the growth rates predicted a priori by an in silico model (Fong and Palsson, Nat. Genet. 36:1056-1058 (2004)). The growth improvements brought about by adaptive evolution can be accompanied by enhanced rates of fatty alcohol, fatty aldehyde or fatty acid production. The strains are generally adaptively evolved in replicate, running in parallel, to account for differences in the evolutionary patterns that can be exhibited by a host organism (Fong and Palsson, Nat. Genet. 36:1056-1058 (2004); Fong et al., J. Bacteriol. 185:6400-6408 (2003); Ibarra et al., Nature 420:186-189 (2002)) that could potentially result in one strain having superior production qualities over the others. Evolutions can be run for a period of time, typically 2-6 weeks, depending upon the rate of growth improvement attained. In general, evolutions are stopped once a stable phenotype is obtained.

Following the adaptive evolution process, the new strains are characterized again by measuring the growth rate, the substrate uptake rate, and the product/byproduct secretion rate. These results are compared to the theoretical predictions by plotting actual growth and production yields along side the production envelopes from metabolic modeling. The most successful design/evolution combinations are chosen to pursue further, and are characterized in lab-scale batch and continuous fermentations. The growth-coupled biochemical production concept behind the methods disclosed herein such as OptKnock approach should also result in the generation of genetically stable overproducers. Thus, the cultures are maintained in continuous mode for an extended period of time, for example, one month or more, to evaluate long-term stability. Periodic samples can be taken to ensure that yield and productivity are maintained.

Adaptive evolution is a powerful technique that can be used to increase growth rates of mutant or engineered microbial strains, or of wild-type strains growing under unnatural environmental conditions. It is especially useful for strains designed via methods such as OptKnock, which results in growth-coupled product formation. Therefore, evolution toward optimal growing strains will indirectly optimize production as well. Unique strains of E. coli K-12 MG1655 were created through gene knockouts and adaptive evolution. (Fong and Palsson, Nat. Genet. 36:1056-1058 (2004)). In this work, all adaptive evolutionary cultures were maintained in prolonged exponential growth by serial passage of batch cultures into fresh medium before the stationary phase was reached, thus rendering growth rate as the primary selection pressure. Knockout strains were constructed and evolved on minimal medium supplemented with different carbon substrates (four for each knockout strain). Evolution cultures were carried out in duplicate or triplicate, giving a total of 50 evolution knockout strains. The evolution cultures were maintained in exponential growth until a stable growth rate was reached. The computational predictions were accurate (within 10%) at predicting the post-evolution growth rate of the knockout strains in 38 out of the 50 cases examined. Furthermore, a combination of OptKnock design with adaptive evolution has led to improved lactic acid production strains. (Fong et al., Biotechnol. Bioeng. 91:643-648 (2005)). Similar methods can be applied to the strains disclosed herein and applied to various host strains.

There are a number of developed technologies for carrying out adaptive evolution. Exemplary methods are disclosed herein. In some embodiments, optimization of a non-naturally occurring organism of the present invention includes utilizing adaptive evolution techniques to increase fatty alcohol, fatty aldehyde or fatty acid production and/or stability of the producing strain.

Serial culture involves repetitive transfer of a small volume of grown culture to a much larger vessel containing fresh growth medium. When the cultured organisms have grown to saturation in the new vessel, the process is repeated. This method has been used to achieve the longest demonstrations of sustained culture in the literature (Lenski and Travisano, Proc. Natl. Acad. Sci. USA 91:6808-6814 (1994)) in experiments which clearly demonstrated consistent improvement in reproductive rate over a period of years. Typically, transfer of cultures is usually performed during exponential phase, so each day the transfer volume is precisely calculated to maintain exponential growth through the next 24 hour period. Manual serial dilution is inexpensive and easy to parallelize.

In continuous culture the growth of cells in a chemostat represents an extreme case of dilution in which a very high fraction of the cell population remains. As a culture grows and becomes saturated, a small proportion of the grown culture is replaced with fresh media, allowing the culture to continually grow at close to its maximum population size. Chemostats have been used to demonstrate short periods of rapid improvement in reproductive rate (Dykhuizen, Methods Enzymol. 613-631 (1993)). The potential usefulness of these devices was recognized, but traditional chemostats were unable to sustain long periods of selection for increased reproduction rate, due to the unintended selection of dilution-resistant (static) variants. These variants are able to resist dilution by adhering to the surface of the chemostat, and by doing so, outcompete less adherent individuals, including those that have higher reproductive rates, thus obviating the intended purpose of the device (Chao and Ramsdell, J. Gen. Microbiol. 20:132-138 (1985)). One possible way to overcome this drawback is the implementation of a device with two growth chambers, which periodically undergo transient phases of sterilization, as described previously (Marliere and Mutzel, U.S. Pat. No. 6,686,194).

Evolugator™ is a continuous culture device developed by Evolugate, LLC (Gainesville, Fla.) and exhibits significant time and effort savings over traditional evolution techniques (de Crecy et al., Appl. Microbiol. Biotechnol. 77:489-496 (2007)). The cells are maintained in prolonged exponential growth by the serial passage of batch cultures into fresh medium before the stationary phase is attained. By automating optical density measurement and liquid handling, the Evolugator™ can perform serial transfer at high rates using large culture volumes, thus approaching the efficiency of a chemostat in evolution of cell fitness. For example, a mutant of Acinetobacter sp ADP1 deficient in a component of the translation apparatus, and having severely hampered growth, was evolved in 200 generations to 80% of the wild-type growth rate. However, in contrast to the chemostat which maintains cells in a single vessel, the machine operates by moving from one “reactor” to the next in subdivided regions of a spool of tubing, thus eliminating any selection for wall-growth. The transfer volume is adjustable, and normally set to about 50%. A drawback to this device is that it is large and costly, thus running large numbers of evolutions in parallel is not practical. Furthermore, gas addition is not well regulated, and strict anaerobic conditions are not maintained with the current device configuration. Nevertheless, this is an alternative method to adaptively evolve a production strain.

As disclosed herein, a nucleic acid encoding a desired activity of a fatty alcohol, fatty aldehyde or fatty acid pathway can be introduced into a host organism. In some cases, it can be desirable to modify an activity of a fatty alcohol, fatty aldehyde or fatty acid pathway enzyme or protein to increase production of fatty alcohol, fatty aldehyde or fatty acid. For example, known mutations that increase the activity of a protein or enzyme can be introduced into an encoding nucleic acid molecule. Additionally, optimization methods can be applied to increase the activity of an enzyme or protein and/or decrease an inhibitory activity, for example, decrease the activity of a negative regulator.

One such optimization method is directed evolution. Directed evolution is a powerful approach that involves the introduction of mutations targeted to a specific gene in order to improve and/or alter the properties of an enzyme. Improved and/or altered enzymes can be identified through the development and implementation of sensitive high-throughput screening assays that allow the automated screening of many enzyme variants (for example, >10⁴). Iterative rounds of mutagenesis and screening typically are performed to afford an enzyme with optimized properties. Computational algorithms that can help to identify areas of the gene for mutagenesis also have been developed and can significantly reduce the number of enzyme variants that need to be generated and screened. Numerous directed evolution technologies have been developed (for reviews, see Hibbert et al., Biomol. Eng 22:11-19 (2005); Huisman and Lalonde, In Biocatalysis in the pharmaceutical and biotechnology industries pgs. 717-742 (2007), Patel (ed.), CRC Press; Otten and Quax. Biomol. Eng 22:1-9 (2005); and Sen et al., Appl Biochem. Biotechnol 143:212-223 (2007)) to be effective at creating diverse variant libraries, and these methods have been successfully applied to the improvement of a wide range of properties across many enzyme classes. Enzyme characteristics that have been improved and/or altered by directed evolution technologies include, for example: selectivity/specificity, for conversion of non-natural substrates; temperature stability, for robust high temperature processing; pH stability, for bioprocessing under lower or higher pH conditions; substrate or product tolerance, so that high product titers can be achieved; binding (K_(m)), including broadening substrate binding to include non-natural substrates; inhibition (K_(i)), to remove inhibition by products, substrates, or key intermediates; activity (kcat), to increases enzymatic reaction rates to achieve desired flux; expression levels, to increase protein yields and overall pathway flux; oxygen stability, for operation of air sensitive enzymes under aerobic conditions; and anaerobic activity, for operation of an aerobic enzyme in the absence of oxygen.

Described below in more detail are exemplary methods that have been developed for the mutagenesis and diversification of genes to target desired properties of specific enzymes. Such methods are well known to those skilled in the art. Any of these can be used to alter and/or optimize the activity of a fatty alcohol, fatty aldehyde or fatty acid pathway enzyme or protein.

EpPCR (Pritchard et al., J Theor. Biol. 234:497-509 (2005)) introduces random point mutations by reducing the fidelity of DNA polymerase in PCR reactions by the addition of Mn²⁺ ions, by biasing dNTP concentrations, or by other conditional variations. The five step cloning process to confine the mutagenesis to the target gene of interest involves: 1) error-prone PCR amplification of the gene of interest; 2) restriction enzyme digestion; 3) gel purification of the desired DNA fragment; 4) ligation into a vector; 5) transformation of the gene variants into a suitable host and screening of the library for improved performance. This method can generate multiple mutations in a single gene simultaneously, which can be useful to screen a larger number of potential variants having a desired activity. A high number of mutants can be generated by EpPCR, so a high-throughput screening assay or a selection method, for example, using robotics, is useful to identify those with desirable characteristics.

Error-prone Rolling Circle Amplification (epRCA) (Fujii et al., Nucleic Acids Res. 32:e145 (2004); and Fujii et al., Nat. Protoc. 1:2493-2497 (2006)) has many of the same elements as epPCR except a whole circular plasmid is used as the template and random 6-mers with exonuclease resistant thiophosphate linkages on the last 2 nucleotides are used to amplify the plasmid followed by transformation into cells in which the plasmid is re-circularized at tandem repeats. Adjusting the Mn²⁺ concentration can vary the mutation rate somewhat. This technique uses a simple error-prone, single-step method to create a full copy of the plasmid with 3-4 mutations/kbp. No restriction enzyme digestion or specific primers are required. Additionally, this method is typically available as a commercially available kit.

DNA or Family Shuffling (Stemmer, Proc Natl Acad Sci USA 91:10747-10751 (1994)); and Stemmer, Nature 370:389-391 (1994)) typically involves digestion of two or more variant genes with nucleases such as Dnase I or EndoV to generate a pool of random fragments that are reassembled by cycles of annealing and extension in the presence of DNA polymerase to create a library of chimeric genes. Fragments prime each other and recombination occurs when one copy primes another copy (template switch). This method can be used with >1 kbp DNA sequences. In addition to mutational recombinants created by fragment reassembly, this method introduces point mutations in the extension steps at a rate similar to error-prone PCR. The method can be used to remove deleterious, random and neutral mutations.

Staggered Extension (StEP) (Zhao et al., Nat. Biotechnol. 16:258-261 (1998)) entails template priming followed by repeated cycles of 2 step PCR with denaturation and very short duration of annealing/extension (as short as 5 sec). Growing fragments anneal to different templates and extend further, which is repeated until full-length sequences are made. Template switching means most resulting fragments have multiple parents. Combinations of low-fidelity polymerases (Taq and Mutazyme) reduce error-prone biases because of opposite mutational spectra.

In Random Priming Recombination (RPR) random sequence primers are used to generate many short DNA fragments complementary to different segments of the template (Shao et al., Nucleic Acids Res 26:681-683 (1998)). Base misincorporation and mispriming via epPCR give point mutations. Short DNA fragments prime one another based on homology and are recombined and reassembled into full-length by repeated thermocycling. Removal of templates prior to this step assures low parental recombinants. This method, like most others, can be performed over multiple iterations to evolve distinct properties. This technology avoids sequence bias, is independent of gene length, and requires very little parent DNA for the application.

In Heteroduplex Recombination linearized plasmid DNA is used to form heteroduplexes that are repaired by mismatch repair (Volkov et al, Nucleic Acids Res. 27:e18 (1999); and Volkov et al., Methods Enzymol. 328:456-463 (2000)). The mismatch repair step is at least somewhat mutagenic. Heteroduplexes transform more efficiently than linear homoduplexes. This method is suitable for large genes and whole operons.

Random Chimeragenesis on Transient Templates (RACHITT) (Coco et al., Nat. Biotechnol. 19:354-359 (2001)) employs Dnase I fragmentation and size fractionation of single stranded DNA (ssDNA). Homologous fragments are hybridized in the absence of polymerase to a complementary ssDNA scaffold. Any overlapping unhybridized fragment ends are trimmed down by an exonuclease. Gaps between fragments are filled in and then ligated to give a pool of full-length diverse strands hybridized to the scaffold, which contains U to preclude amplification. The scaffold then is destroyed and is replaced by a new strand complementary to the diverse strand by PCR amplification. The method involves one strand (scaffold) that is from only one parent while the priming fragments derive from other genes, and the parent scaffold is selected against. Thus, no reannealing with parental fragments occurs. Overlapping fragments are trimmed with an exonuclease. Otherwise, this is conceptually similar to DNA shuffling and StEP. Therefore, there should be no siblings, few inactives, and no unshuffled parentals. This technique has advantages in that few or no parental genes are created and many more crossovers can result relative to standard DNA shuffling.

Recombined Extension on Truncated templates (RETT) entails template switching of unidirectionally growing strands from primers in the presence of unidirectional ssDNA fragments used as a pool of templates (Lee et al., J. Molec. Catalysis 26:119-129 (2003)). No DNA endonucleases are used. Unidirectional ssDNA is made by DNA polymerase with random primers or serial deletion with exonuclease. Unidirectional ssDNA are only templates and not primers. Random priming and exonucleases do not introduce sequence bias as true of enzymatic cleavage of DNA shuffling/RACHITT. RETT can be easier to optimize than StEP because it uses normal PCR conditions instead of very short extensions. Recombination occurs as a component of the PCR steps, that is, no direct shuffling. This method can also be more random than StEP due to the absence of pauses.

In Degenerate Oligonucleotide Gene Shuffling (DOGS) degenerate primers are used to control recombination between molecules; (Bergquist and Gibbs, Methods Mol. Biol 352:191-204 (2007); Bergquist et al., Biomol. Eng 22:63-72 (2005); Gibbs et al., Gene 271:13-20 (2001)) this can be used to control the tendency of other methods such as DNA shuffling to regenerate parental genes. This method can be combined with random mutagenesis (epPCR) of selected gene segments. This can be a good method to block the reformation of parental sequences. No endonucleases are needed. By adjusting input concentrations of segments made, one can bias towards a desired backbone. This method allows DNA shuffling from unrelated parents without restriction enzyme digests and allows a choice of random mutagenesis methods.

Incremental Truncation for the Creation of Hybrid Enzymes (ITCHY) creates a combinatorial library with 1 base pair deletions of a gene or gene fragment of interest (Ostermeier et al., Proc. Natl. Acad. Sci. USA 96:3562-3567 (1999); and Ostermeier et al., Nat. Biotechnol. 17:1205-1209 (1999)). Truncations are introduced in opposite direction on pieces of 2 different genes. These are ligated together and the fusions are cloned. This technique does not require homology between the 2 parental genes. When ITCHY is combined with DNA shuffling, the system is called SCRATCHY (see below). A major advantage of both is no need for homology between parental genes; for example, functional fusions between an E. coli and a human gene were created via ITCHY. When ITCHY libraries are made, all possible crossovers are captured.

Thio-Incremental Truncation for the Creation of Hybrid Enzymes (THIO-ITCHY) is similar to ITCHY except that phosphothioate dNTPs are used to generate truncations (Lutz et al., Nucleic Acids Res 29:E16 (2001)). Relative to ITCHY, THIO-ITCHY can be easier to optimize, provide more reproducibility, and adjustability.

SCRATCHY combines two methods for recombining genes, ITCHY and DNA shuffling (Lutz et al., Proc. Natl. Acad. Sci. USA 98:11248-11253 (2001)). SCRATCHY combines the best features of ITCHY and DNA shuffling. First, ITCHY is used to create a comprehensive set of fusions between fragments of genes in a DNA homology-independent fashion. This artificial family is then subjected to a DNA-shuffling step to augment the number of crossovers. Computational predictions can be used in optimization. SCRATCHY is more effective than DNA shuffling when sequence identity is below 80%.

In Random Drift Mutagenesis (RNDM) mutations are made via epPCR followed by screening/selection for those retaining usable activity (Bergquist et al., Biomol. Eng. 22:63-72 (2005)). Then, these are used in DOGS to generate recombinants with fusions between multiple active mutants or between active mutants and some other desirable parent. Designed to promote isolation of neutral mutations; its purpose is to screen for retained catalytic activity whether or not this activity is higher or lower than in the original gene. RNDM is usable in high throughput assays when screening is capable of detecting activity above background. RNDM has been used as a front end to DOGS in generating diversity. The technique imposes a requirement for activity prior to shuffling or other subsequent steps; neutral drift libraries are indicated to result in higher/quicker improvements in activity from smaller libraries. Though published using epPCR, this could be applied to other large-scale mutagenesis methods.

Sequence Saturation Mutagenesis (SeSaM) is a random mutagenesis method that: 1) generates a pool of random length fragments using random incorporation of a phosphothioate nucleotide and cleavage; this pool is used as a template to 2) extend in the presence of “universal” bases such as inosine; 3) replication of an inosine-containing complement gives random base incorporation and, consequently, mutagenesis (Wong et al., Biotechnol. J. 3:74-82 (2008); Wong et al., Nucleic Acids Res. 32:e26 (2004); and Wong et al., Anal. Biochem. 341:187-189 (2005)). Using this technique it can be possible to generate a large library of mutants within 2 to 3 days using simple methods. This technique is non-directed in comparison to the mutational bias of DNA polymerases. Differences in this approach makes this technique complementary (or an alternative) to epPCR.

In Synthetic Shuffling, overlapping oligonucleotides are designed to encode “all genetic diversity in targets” and allow a very high diversity for the shuffled progeny (Ness et al., Nat. Biotechnol. 20:1251-1255 (2002)). In this technique, one can design the fragments to be shuffled. This aids in increasing the resulting diversity of the progeny. One can design sequence/codon biases to make more distantly related sequences recombine at rates approaching those observed with more closely related sequences. Additionally, the technique does not require physically possessing the template genes.

Nucleotide Exchange and Excision Technology NexT exploits a combination of dUTP incorporation followed by treatment with uracil DNA glycosylase and then piperidine to perform endpoint DNA fragmentation (Muller et al., Nucleic Acids Res. 33:e117 (2005)). The gene is reassembled using internal PCR primer extension with proofreading polymerase. The sizes for shuffling are directly controllable using varying dUPT::dTTP ratios. This is an end point reaction using simple methods for uracil incorporation and cleavage. Other nucleotide analogs, such as 8-oxo-guanine, can be used with this method. Additionally, the technique works well with very short fragments (86 bp) and has a low error rate. The chemical cleavage of DNA used in this technique results in very few unshuffled clones.

In Sequence Homology-Independent Protein Recombination (SHIPREC), a linker is used to facilitate fusion between two distantly related or unrelated genes. Nuclease treatment is used to generate a range of chimeras between the two genes. These fusions result in libraries of single-crossover hybrids (Sieber et al., Nat. Biotechnol. 19:456-460 (2001)). This produces a limited type of shuffling and a separate process is required for mutagenesis. In addition, since no homology is needed, this technique can create a library of chimeras with varying fractions of each of the two unrelated parent genes. SHIPREC was tested with a heme-binding domain of a bacterial CP450 fused to N-terminal regions of a mammalian CP450; this produced mammalian activity in a more soluble enzyme.

In Gene Site Saturation Mutagenesis™ (GSSM™) the starting materials are a supercoiled dsDNA plasmid containing an insert and two primers which are degenerate at the desired site of mutations (Kretz et al., Methods Enzymol. 388:3-11 (2004)). Primers carrying the mutation of interest, anneal to the same sequence on opposite strands of DNA. The mutation is typically in the middle of the primer and flanked on each side by approximately 20 nucleotides of correct sequence. The sequence in the primer is NNN or NNK (coding) and MNN (noncoding) (N=all 4, K=G, T, M=A, C). After extension, DpnI is used to digest dam-methylated DNA to eliminate the wild-type template. This technique explores all possible amino acid substitutions at a given locus (that is, one codon). The technique facilitates the generation of all possible replacements at a single-site with no nonsense codons and results in equal to near-equal representation of most possible alleles. This technique does not require prior knowledge of the structure, mechanism, or domains of the target enzyme. If followed by shuffling or Gene Reassembly, this technology creates a diverse library of recombinants containing all possible combinations of single-site up-mutations. The usefulness of this technology combination has been demonstrated for the successful evolution of over 50 different enzymes, and also for more than one property in a given enzyme.

Combinatorial Cassette Mutagenesis (CCM) involves the use of short oligonucleotide cassettes to replace limited regions with a large number of possible amino acid sequence alterations (Reidhaar-Olson et al. Methods Enzymol. 208:564-586 (1991); and Reidhaar-Olson et al. Science 241:53-57 (1988)). Simultaneous substitutions at two or three sites are possible using this technique. Additionally, the method tests a large multiplicity of possible sequence changes at a limited range of sites. This technique has been used to explore the information content of the lambda repressor DNA-binding domain.

Combinatorial Multiple Cassette Mutagenesis (CMCM) is essentially similar to CCM except it is employed as part of a larger program: 1) use of epPCR at high mutation rate to 2) identify hot spots and hot regions and then 3) extension by CMCM to cover a defined region of protein sequence space (Reetz et al., Angew. Chem. Int. Ed Engl. 40:3589-3591 (2001)). As with CCM, this method can test virtually all possible alterations over a target region. If used along with methods to create random mutations and shuffled genes, it provides an excellent means of generating diverse, shuffled proteins. This approach was successful in increasing, by 51-fold, the enantioselectivity of an enzyme.

In the Mutator Strains technique, conditional is mutator plasmids allow increases of 20 to 4000-X in random and natural mutation frequency during selection and block accumulation of deleterious mutations when selection is not required (Selifonova et al., Appl. Environ. Microbiol. 67:3645-3649 (2001)). This technology is based on a plasmid-derived mutD5 gene, which encodes a mutant subunit of DNA polymerase III. This subunit binds to endogenous DNA polymerase III and compromises the proofreading ability of polymerase III in any strain that harbors the plasmid. A broad-spectrum of base substitutions and frameshift mutations occur. In order for effective use, the mutator plasmid should be removed once the desired phenotype is achieved; this is accomplished through a temperature sensitive (ts) origin of replication, which allows for plasmid curing at 41° C. It should be noted that mutator strains have been explored for quite some time (see Low et al., J. Mol. Biol. 260:359-3680 (1996)). In this technique, very high spontaneous mutation rates are observed. The conditional property minimizes non-desired background mutations. This technology could be combined with adaptive evolution to enhance mutagenesis rates and more rapidly achieve desired phenotypes.

Look-Through Mutagenesis (LTM) is a multidimensional mutagenesis method that assesses and optimizes combinatorial mutations of selected amino acids (Rajpal et al., Proc. Natl. Acad. Sci. USA 102:8466-8471 (2005)). Rather than saturating each site with all possible amino acid changes, a set of nine is chosen to cover the range of amino acid R-group chemistry. Fewer changes per site allows multiple sites to be subjected to this type of mutagenesis. A >800-fold increase in binding affinity for an antibody from low nanomolar to picomolar has been achieved through this method. This is a rational approach to minimize the number of random combinations and can increase the ability to find improved traits by greatly decreasing the numbers of clones to be screened. This has been applied to antibody engineering, specifically to increase the binding affinity and/or reduce dissociation. The technique can be combined with either screens or selections.

Gene Reassembly is a DNA shuffling method that can be applied to multiple genes at one time or to create a large library of chimeras (multiple mutations) of a single gene (Tunable GeneReassembly™ (TGR™) Technology supplied by Verenium Corporation). Typically this technology is used in combination with ultra-high-throughput screening to query the represented sequence space for desired improvements. This technique allows multiple gene recombination independent of homology. The exact number and position of cross-over events can be predetermined using fragments designed via bioinformatic analysis. This technology leads to a very high level of diversity with virtually no parental gene reformation and a low level of inactive genes. Combined with GSSM™, a large range of mutations can be tested for improved activity. The method allows “blending” and “fine tuning” of DNA shuffling, for example, codon usage can be optimized.

In Silico Protein Design Automation (PDA) is an optimization algorithm that anchors the structurally defined protein backbone possessing a particular fold, and searches sequence space for amino acid substitutions that can stabilize the fold and overall protein energetics (Hayes et al., Proc. Natl. Acad. Sci. USA 99:15926-15931 (2002)). This technology uses in silico structure-based entropy predictions in order to search for structural tolerance toward protein amino acid variations. Statistical mechanics is applied to calculate coupling interactions at each position. Structural tolerance toward amino acid substitution is a measure of coupling. Ultimately, this technology is designed to yield desired modifications of protein properties while maintaining the integrity of structural characteristics. The method computationally assesses and allows filtering of a very large number of possible sequence variants (10⁵⁰). The choice of sequence variants to test is related to predictions based on the most favorable thermodynamics. Ostensibly only stability or properties that are linked to stability can be effectively addressed with this technology. The method has been successfully used in some therapeutic proteins, especially in engineering immunoglobulins. In silico predictions avoid testing extraordinarily large numbers of potential variants. Predictions based on existing three-dimensional structures are more likely to succeed than predictions based on hypothetical structures. This technology can readily predict and allow targeted screening of multiple simultaneous mutations, something not possible with purely experimental technologies due to exponential increases in numbers.

Iterative Saturation Mutagenesis (ISM) involves: 1) using knowledge of structure/function to choose a likely site for enzyme improvement; 2) performing saturation mutagenesis at chosen site using a mutagenesis method such as Stratagene QuikChange (Stratagene; San Diego Calif.); 3) screening/selecting for desired properties; and 4) using improved clone(s), start over at another site and continue repeating until a desired activity is achieved (Reetz et al., Nat. Protoc. 2:891-903 (2007); and Reetz et al., Angew. Chem. Int. Ed Engl. 45:7745-7751 (2006)). This is a proven methodology, which assures all possible replacements at a given position are made for screening/selection.

Any of the aforementioned methods for mutagenesis can be used alone or in any combination. Additionally, any one or combination of the directed evolution methods can be used in conjunction with adaptive evolution techniques, as described herein.

It is understood that modifications which do not substantially affect the activity of the various embodiments of this invention are also provided within the definition of the invention provided herein. Accordingly, the following examples are intended to illustrate but not limit the present invention.

Example I Production of Fatty Alcohols and Fatty Aldehydes by MI-FAE Cycle and Acyl-CoA Termination Pathways

Encoding nucleic acids and species that can be used as sources for conferring fatty alcohol and fatty aldehyde production capability onto a host microbial organism are exemplified further below.

Multienzyme Complexes

In one exemplary embodiment, the genes fadA and fadB encode a multienzyme complex that exhibits three constituent activities of the malonyl-CoA independent FAS pathway, namely, ketoacyl-CoA thiolase, 3-hydroxyacyl-CoA dehydrogenase, and enoyl-CoA hydratase activities (Nakahigashi, K. and H. Inokuchi, Nucleic Acids Research 18:4937 (1990); Yang et al., Journal of Bacteriology 173:7405-7406 (1991); Yang et al, Journal of Biological Chemistry 265:10424-10429 (1990); Yang et al., Biochemistry 30:6788-6795 (1990)). The fadI and fadJ genes encode similar activities which can substitute for the above malonyl-CoA independent FAS conferring genes fadA and fadB. The acyl-Coa dehydrogenase of E. coli is encoded by fadE (Campbell et al, J Bacteriol 184: 3759-64)). This enzyme catalyzes the rate-limiting step of beta-oxidation (O'Brien et al, J Bacteriol 132:532-40 (1977)). The nucleic acid sequences for each of the above fad genes are well known in the art and can be accessed in the public databases such as Genbank using the following accession numbers.

Protein GenBank ID GI Number Organism fadA YP_026272.1 49176430 Escherichia coli fadB NP_418288.1 16131692 Escherichia coli fadI NP_416844.1 16130275 Escherichia coli fadJ NP_416843.1 16130274 Escherichia coli fadR NP_415705.1 16129150 Escherichia coli fadE AAC73325.2 87081702 Escherichia coli

Step A. Thiolase

Thiolase enzymes, also know as beta-keto thiolase, acyl-CoA C-acetyltransferase, acyl-CoA:acetyl-CoA C-acyltransferase, 3-oxoacyl-CoA thiolase, 3-ketoacyl-CoA thiolase, beta-ketoacyl-CoA thiolase, and acyl-CoA thiolase, that are suitable for fatty alcohol, fatty aldehyde or fatty acid production are described herein (FIGS. 1A and 6A). Exemplary acetoacetyl-CoA thiolase enzymes include the gene products of atoB and homolog yqeF from E. coli (Martin et al., Nat. Biotechnol 21:796-802 (2003)), thlA and thlB from C. acetobutylicum (Hanai et al., Appl Environ Microbiol 73:7814-7818 (2007); Winzer et al., J. Mol. Microbiol Biotechnol 2:531-541 (2000)), and ERG10 from S. cerevisiae (Hiser et al., J. Biol. Chem. 269:31383-31389 (1994)). A degradative thiolase of S. cerevisiae is encoded by POT1. Another candidate thiolase is the phaA gene product of R. eutropha (Jenkins et al, Journal of Bacteriology 169:42-52 (1987)). The acetoacetyl-CoA thiolase from Zoogloea ramigera is irreversible in the biosynthetic direction and a crystal structure is available (Merilainen et al, Biochem 48: 11011-25 (2009)). Accession numbers for these thiolases and homologs are included in the table below.

Protein GenBank ID GI Number Organism atoB NP_416728 16130161 Escherichia coli yqeF NP_417321.2 90111494 Escherichia coli thlA NP_349476.1 15896127 Clostridium acetobutylicum thlB NP_149242.1 15004782 Clostridium acetobutylicum ERG10 NP_015297 6325229 Saccharomyces cerevisiae POT1 NP_012106.1 6322031 Saccharomyces cerevisiae phaA YP_725941 113867452 Ralstonia eutropha phbA P07097.4 135759 Zoogloea ramigera h16_A1713 YP_726205.1 113867716 Ralstonia eutropha pcaF YP_728366.1 116694155 Ralstonia eutropha h16_B1369 YP_840888.1 116695312 Ralstonia eutropha h16_A0170 YP_724690.1 113866201 Ralstonia eutropha h16_A0462 YP_724980.1 113866491 Ralstonia eutropha h16_A1528 YP_726028.1 113867539 Ralstonia eutropha h16_B0381 YP_728545.1 116694334 Ralstonia eutropha h16_B0662 YP_728824.1 116694613 Ralstonia eutropha h16_B0759 YP_728921.1 116694710 Ralstonia eutropha h16_B0668 YP_728830.1 116694619 Ralstonia eutropha h16_A1720 YP_726212.1 113867723 Ralstonia eutropha h16_A1887 YP_726356.1 113867867 Ralstonia eutropha bktB YP_002005382.1 194289475 Cupriavidus taiwanensis Rmet_1362 YP_583514.1 94310304 Ralstonia metallidurans Bphy_0975 YP_001857210.1 186475740 Burkholderia phymatum

Many thiolase enzymes catalyze the formation of longer-chain acyl-CoA products. Exemplary thiolases include, for example, 3-oxoadipyl-CoA thiolase (EC 2.3.1.174) and acyl-CoA thiolase (EC 2.3.1.16). 3-Oxoadipyl-CoA thiolase converts succinyl-CoA and acetyl-CoA to 3-oxoadipyl-CoA, and is a key enzyme of the beta-ketoadipate pathway for aromatic compound degradation. The enzyme is widespread in soil bacteria and fungi including Pseudomonas putida (Harwood et al., J Bacteriol. 176:6479-6488 (1994)) and Acinetobacter calcoaceticus (Doten et al., J Bacteriol. 169:3168-3174 (1987)). The gene products encoded by pcaF in Pseudomonas strain B 13 (Kaschabek et al., J Bacteriol. 184:207-215 (2002)), phaD in Pseudomonas putida U (Olivera et al., Proc. Natl. Acad. Sci U.S.A. 95:6419-6424 (1998)), paaE in Pseudomonas fluorescens ST (Di et al., Arch. Microbiol 188:117-125 (2007)), and paaJ from E. coli (Nogales et al., Microbiology 153:357-365 (2007)) also catalyze this transformation. Several beta-ketothiolases exhibit significant and selective activities in the oxoadipyl-CoA forming direction including bkt from Pseudomonas putida, pcaF and bkt from Pseudomonas aeruginosa PAO1, bkt from Burkholderia ambifaria AMMD, paaJ from E. coli, and phaD from P. putida. Two gene products of Ralstonia eutropha (formerly known as Alcaligenes eutrophus), encoded by genes bktB and bktC, catalyze the formation of 3-oxopimeloyl-CoA (Slater et al., J. Bacteriol. 180:1979-1987 (1998); Haywood et al., FEMS Microbiology Letters 52:91-96 (1988)). The sequence of the BktB protein is known; however, the sequence of the BktC protein has not been reported. BktB is also active on substrates of length C6 and C8 (Machado et al, Met Eng in press (2012)). The pim operon of Rhodopseudomonas palustris also encodes a beta-ketothiolase, encoded by pimB, predicted to catalyze this transformation in the degradative direction during benzoyl-CoA degradation (Harrison et al., Microbiology 151:727-736 (2005)). A beta-ketothiolase enzyme candidate in S. aciditrophicus was identified by sequence homology to bktB (43% identity, evalue=1e-93).

GenBank Accession Gene name GI# # Organism paaJ 16129358 NP_415915.1 Escherichia coli pcaF 17736947 AAL02407 Pseudomonas knackmussii (B13) phaD 3253200 AAC24332.1 Pseudomonas putida pcaF 506695 AAA85138.1 Pseudomonas putida pcaF 141777 AAC37148.1 Acinetobacter calcoaceticus paaE 106636097 ABF82237.1 Pseudomonas fluorescens bkt 115360515 YP_777652.1 Burkholderia ambifaria AMMD bkt 9949744 AAG06977.1 Pseudomonas aeruginosa PAO1 pcaF 9946065 AAG03617.1 Pseudomonas aeruginosa PAO1 bktB YP_725948 11386745 Ralstonia eutropha pimB CAE29156 39650633 Rhodopseudomonas palustris syn_02642 YP_462685.1 85860483 Syntrophus aciditrophicus

Acyl-CoA thiolase (EC 2.3.1.16) enzymes involved in the beta-oxidation cycle of fatty acid degradation exhibit activity on a broad range of acyl-CoA substrates of varying chain length. Exemplary acyl-CoA thiolases are found in Arabidopsis thaliana (Cruz et al, Plant Physiol 135:85-94 (2004)), Homo sapiens (Mannaerts et al, Cell Biochem Biphys 32:73-87 (2000)), Helianthus annuus (Schiedel et al, Prot Expr Purif 33:25-33 (2004)). The chain length specificity of thiolase enzymes can be assayed by methods well known in the art (Wrensford et al, Anal Biochem 192:49-54 (1991)). A peroxisomal thiolase found in rat liver catalyze the acetyl-CoA dependent formation of longer chain acyl-CoA products from octanoyl-CoA (Horie et al, Arch Biochem Biophys 274: 64-73 (1989); Hijikata et al, J Biol Chem 265, 4600-4606 (1990)).

Protein GenBank ID GI Number Organism AY308827.1:1 . . . 1350 AAQ77242.1 34597334 Helianthus annuus KAT2 Q56WD9.2 73919871 Arabidopsis thaliana KAT1 Q8LF48.2 73919870 Arabidopsis thaliana KAT5 Q570C8.2 73919872 Arabidopsis thaliana ACAA1 P09110.2 135751 Homo sapiens LCTHIO AAF04612.1 6165556 Sus scrofa Acaa1a NP_036621.1 6978429 Rattus norvegicus Acaa1b NP_001035108.1 90968642 Rattus norvegicus Acaa2 NP_569117.1 18426866 Rattus norvegicus

Acetoacetyl-CoA can also be synthesized from acetyl-CoA and malonyl-CoA by acetoacetyl-CoA synthase (EC 2.3.1.194). This enzyme (FhsA) has been characterized in the soil bacterium Streptomyces sp. CL 190 where it participates in mevalonate biosynthesis (Okamura et al, PNAS USA 107:11265-70 (2010)). As this enzyme catalyzes an essentially irreversible reaction, it is particularly useful for metabolic engineering applications for overproducing metabolites, fuels or chemicals derived from acetoacetyl-CoA such as long chain alcohols. Other acetoacetyl-CoA synthase genes can be identified by sequence homology to fhsA. Acyl-CoA synthase enzymes such as fhsA and homologs can be engineered or evolved to accept longer acyl-CoA substrates by methods known in the art.

Protein GenBank ID GI Number Organism fhsA BAJ83474.1 325302227 Streptomyces sp CL190 AB183750.1:11991 . . . 12971 BAD86806.1 57753876 Streptomyces sp. KO-3988 epzT ADQ43379.1 312190954 Streptomyces cinnamonensis ppzT CAX48662.1 238623523 Streptomyces anulatus O31_22085 ZP_09840373.1 378817444 Nocardia brasiliensis

Chain length selectivity of selected thiolase enzymes described above is summarized in the table below.

Chain length Gene Organism C4 atoB Escherichia coli C6 phaD Pseudomonas putida C6-C8 bktB Ralstonia eutropha C10-C16 Acaala Rattus norvegicus

Step B. 3-Oxoacyl-CoA Reductase

3-Oxoacyl-CoA reductases (also known as 3-hydroxyacyl-CoA dehydrogenases, 3-ketoacyl-CoA reductases, beta-ketoacyl-CoA reductases, beta-hydroxyacyl-CoA dehydrogenases, hydroxyacyl-CoA dehydrogenases, and ketoacyl-CoA reductases) catalyze the reduction of 3-oxoacyl-CoA substrates to 3-hydroxyacyl-CoA products (FIG. 1B and FIG. 6B). These enzymes are often involved in fatty acid beta-oxidation and aromatic degradation pathways. For example, subunits of two fatty acid oxidation complexes in E. coli, encoded by fadB and fadJ, function as 3-hydroxyacyl-CoA dehydrogenases (Binstock et al., Methods Enzymol. 71 Pt C:403-411 (1981)). Knocking out a negative regulator encoded by fadR can be utilized to activate the fadB gene product (Sato et al., J Biosci. Bioeng 103:38-44 (2007)). Another 3-hydroxyacyl-CoA dehydrogenase from E. coli is paaH (Ismail et al., European Journal of Biochemistry 270:3047-3054 (2003)). Additional 3-oxoacyl-CoA enzymes include the gene products of phaC in Pseudomonas putida (Olivera et al., Proc. Natl. Acad. Sci U.S.A. 95:6419-6424 (1998)) and paaC in Pseudomonas fluorescens (Di et al., 188:117-125 (2007)). These enzymes catalyze the reversible oxidation of 3-hydroxyadipyl-CoA to 3-oxoadipyl-CoA during the catabolism of phenylacetate or styrene. Other suitable enzyme candidates include AA072312.1 from E. gracilis (Winkler et al., Plant Physiology 131:753-762 (2003)) and paaC from Pseudomonas putida (Olivera et al., PNAS USA 95:6419-6424 (1998)). Enzymes catalyzing the reduction of acetoacetyl-CoA to 3-hydroxybutyryl-CoA include hbd of Clostridium acetobutylicum (Youngleson et al., J Bacteriol. 171:6800-6807 (1989)), phbB from Zoogloea ramigera (Ploux et al., Eur. J Biochem. 174:177-182 (1988)), phaB from Rhodobacter sphaeroides (Alber et al., Mol. Microbiol 61:297-309 (2006)) and paaH1 of Ralstonia eutropha (Machado et al, Met Eng, In Press (2012)). The Z. ramigera enzyme is NADPH-dependent and also accepts 3-oxopropionyl-CoA as a substrate (Ploux et al., Eur. J Biochem. 174:177-182 (1988)). Additional genes include phaB in Paracoccus denitrificans, Hbd1 (C-terminal domain) and Hbd2 (N-terminal domain) in Clostridium kluyveri (Hillmer and Gottschalk, Biochim. Biophys. Acta 3334:12-23 (1974)) and HSD17B10 in Bos taurus (Wakil et al., J Biol. Chem. 207:631-638 (1954)). The enzyme from Paracoccus denitrificans has been functionally expressed and characterized in E. coli (Yabutani et al., FEMS Microbiol Lett. 133:85-90 (1995)). A number of similar enzymes have been found in other species of Clostridia and in Metallosphaera sedula (Berg et al., Science. 318:1782-1786 (2007)). The enzyme from Candida tropicalis is a component of the peroxisomal fatty acid beta-oxidation multifunctional enzyme type 2 (MFE-2). The dehydrogenase B domain of this protein is catalytically active on acetoacetyl-CoA. The domain has been functionally expressed in E. coli, a crystal structure is available, and the catalytic mechanism is well-understood (Ylianttila et al., Biochem Biophys Res Commun 324:25-30 (2004); Ylianttila et al., J Mol Biol 358:1286-1295 (2006)). 3-Hydroxyacyl-CoA dehydrogenases that accept longer acyl-CoA substrates (eg. EC 1.1.1.35) are typically involved in beta-oxidation. An example is HSD17B10 in Bos taurus (Wakil et al., J Biol. Chem. 207:631-638 (1954)). The pig liver enzyme is preferentially active on short and medium chain acyl-CoA substrates whereas the heart enzyme is less selective (He et al, Biochim Biophys Acta 1392:119-26 (1998)). The S. cerevisiae enzyme FOX2 is active in beta-degradation pathways and also has enoyl-CoA hydratase activity (Hiltunen et al, J Biol Chem 267: 6646-6653 (1992)).

Protein Genbank ID GI number Organism fadB P21177.2 119811 Escherichia coli fadJ P77399.1 3334437 Escherichia coli paaH NP_415913.1 16129356 Escherichia coli Hbd2 EDK34807.1 146348271 Clostridium kluyveri Hbd1 EDK32512.1 146345976 Clostridium kluyveri phaC NP_745425.1 26990000 Pseudomonas putida paaC ABF82235.1 106636095 Pseudomonas fluorescens HSD17B10 O02691.3 3183024 Bos taurus phbB P23238.1 130017 Zoogloea ramigera phaB YP_353825.1 77464321 Rhodobacter sphaeroides paaH1 CAJ91433.1 113525088 Ralstonia eutropha phaB BAA08358 675524 Paracoccus denitrificans Hbd NP_349314.1 15895965 Clostridium acetobutylicum Hbd AAM14586.1 20162442 Clostridium beijerinckii Msed_1423 YP_001191505 146304189 Metallosphaera sedula Msed_0399 YP_001190500 146303184 Metallosphaera sedula Msed_0389 YP_001190490 146303174 Metallosphaera sedula Msed_1993 YP_001192057 146304741 Metallosphaera sedula Fox2 Q02207 399508 Candida tropicalis HSD17B10 O02691.3 3183024 Bos taurus HADH NP_999496.1 47523722 Bos taurus 3HCDH AAO72312.1 29293591 Euglena gracilis FOX2 NP_012934.1 6322861 Saccharomyces cerevisiae

Chain length specificity of selected hydroxyacyl-CoA dehydrogenase enzymes is shown below. Directed evolution can enhance selectivity of enzymes for longer-chain substrates. For example, Machado and coworkers developed a selection platform for directed evolution of chain elongation enzymes that favor longer acyl-CoA substrates. This group evolved paaH1 of Ralstonia eutropha for improved activity on 3-oxo-hexanoyl-CoA (Machado et al, Met Eng, In Press (2012)).

Chain length Gene Organism C4 hbd Clostridium acetobutylicum C5 phbB Zoogloea ramigera C4-C6 paaH1 Ralstonia eutropha C4-C10 HADH Sus scrofa C4-C18 fadB Escherichia coli

Step C. 3-Hydroxyacyl-CoA Dehydratase

3-Hydroxyacyl-CoA dehydratases (eg. EC 4.2.1.17, also known as enoyl-CoA hydratases) catalyze the dehydration of a range of 3-hydroxyacyl-CoA substrates (Roberts et al., Arch. Microbiol 117:99-108 (1978); Agnihotri et al., Bioorg. Med. Chem. 11:9-20 (2003); Conrad et al., J Bacteriol. 118:103-111 (1974)) and can be used in the conversion of 3-hydroxyacyl-CoA to enoyl-CoA (FIGS. 1C and 6C). The ech gene product of Pseudomonas putida catalyzes the conversion of 3-hydroxybutyryl-CoA to crotonyl-CoA (Roberts et al., Arch. Microbiol 117:99-108 (1978)). This transformation is also catalyzed by the crt gene product of Clostridium acetobutylicum, the crt1 gene product of C. kluyveri, and other clostridial organisms Atsumi et al., Metab Eng 10:305-311 (2008); Boynton et al., J Bacteriol. 178:3015-3024 (1996); Hillmer et al., FEBS Lett. 21:351-354 (1972)). Additional enoyl-CoA hydratase candidates are phaA and phaB, of P. putida, and paaA and paaB from P. fluorescens (Olivera et al., Proc. Natl. Acad. Sci U.S.A. 95:6419-6424 (1998)). The gene product of pimF in Rhodopseudomonas palustris is predicted to encode an enoyl-CoA hydratase that participates in pimeloyl-CoA degradation (Harrison et al., Microbiology 151:727-736 (2005)). Lastly, a number of Escherichia coli genes have been shown to demonstrate enoyl-CoA hydratase functionality including maoC (Park et al., J Bacteriol. 185:5391-5397 (2003)), paaF (Ismail et al., Eur. J Biochem. 270:3047-3054 (2003); Park et al., Appl. Biochem. Biotechnol 113-116:335-346 (2004); Park et al., Biotechnol Bioeng 86:681-686 (2004)) and paaG (Ismail et al., Eur. J Biochem. 270:3047-3054 (2003); Park and Lee, Appl. Biochem. Biotechnol 113-116:335-346 (2004); Park and Yup, Biotechnol Bioeng 86:681-686 (2004)). Enzymes with 3-hydroxyacyl-CoA dehydratase activity in S. cerevisiae include PHS1 and FOX2.

GenBank Gene Accession No. GI No. Organism ech NP_745498.1 26990073 Pseudomonas putida crt NP_349318.1 15895969 Clostridium acetobutylicum crt1 YP_001393856 153953091 Clostridium kluyveri phaA ABF82233.1 26990002 Pseudomonas putida phaB ABF82234.1 26990001 Pseudomonas putida paaA NP_745427.1 106636093 Pseudomonas fluorescens paaB NP_745426.1 106636094 Pseudomonas fluorescens pimF CAE29158.1 39650635 Rhodopseudomonas palustris maoC NP_415905.1 16129348 Escherichia coli paaF NP_415911.1 16129354 Escherichia coli paaG NP_415912.1 16129355 Escherichia coli FOX2 NP_012934.1 6322861 Saccharomyces cerevisiae PHS1 NP_012438.1 6322364 Saccharomyces cerevisiae

Enoyl-CoA hydratases involved in beta-oxidation can also be used in an fatty alcohol, fatty aldehyde and fatty acid biosynthetic pathway. For example, the multifunctional MFP2 gene product of Arabidopsis thaliana exhibits an enoyl-CoA reductase activity selective for chain lengths less than or equal to C14 (Arent et al, J Biol Chem 285:24066-77 (2010)). Alternatively, the E. coli gene products of fadA and fadB encode a multienzyme complex involved in fatty acid oxidation that exhibits enoyl-CoA hydratase activity (Yang et al., Biochemistry 30:6788-6795 (1991); Yang, J Bacteriol. 173:7405-7406 (1991); Nakahigashi et al., Nucleic Acids Res. 18:4937 (1990)). The fadI and fadJ genes encode similar functions and are naturally expressed under anaerobic conditions (Campbell et al., Mol. Microbiol 47:793-805 (2003)).

Protein GenBank ID GI Number Organism MFP2 AAD18042.1 4337027 Arabidopsis thaliana fadA YP_026272.1 49176430 Escherichia coli fadB NP_418288.1 16131692 Escherichia coli fadI NP_416844.1 16130275 Escherichia coli fadJ NP_416843.1 16130274 Escherichia coli fadR NP_415705.1 16129150 Escherichia coli

Chain length specificity of selected 3-hydroxyacyl-CoA dehydratase enzymes is shown below.

Chain length Gene Organism C4-C6 crt Clostridium acetobutylicum C4-C7 pimF Rhodopseudomonas palustris  C4-C14 MFP2 Arabidopsis thaliana

Step D. Enoyl-CoA Reductase

Enoyl-CoA reductases (also known as acyl-CoA dehydrogenases, trans-2-enoyl-CoA reductases, or acyl-CoA oxidoreductases) catalyze the conversion of an enoyl-CoA to an acyl-CoA (step D of FIGS. 1 and 6). Exemplary acyl-CoA dehydrogenase or enoyl-CoA reductase (ECR) enzymes are the gene products of fadE of E. coli and Salmonella enterica (Iram et al, J Bacteriol 188:599-608 (2006)). The bcd gene product from Clostridium acetobutylicum (Atsumi et al., 10:305-311 (2008); Boynton et al., J Bacteriol. 178:3015-3024 (1996)) catalyzes the reduction of crotonyl-CoA to butyryl-CoA (EC 1.3.99.2). This enzyme participates in the acetyl-CoA fermentation pathway to butyrate in Clostridial species (Jones et al., Microbiol Rev. 50:484-524 (1986)). Activity of butyryl-CoA reductase can be enhanced by expressing bcd in conjunction with expression of the C. acetobutylicum etfAB genes, which encode an electron transfer flavoprotein. An additional candidate for the enoyl-CoA reductase step is the enoyl-CoA reductase (EC 1.3.1.44) TER from E. gracilis (Hoffmeister et al., J Biol. Chem. 280:4329-4338 (2005)). A construct derived from this sequence following the removal of its mitochondrial targeting leader sequence was cloned in E. coli resulting in an active enzyme. A close homolog of the ECR protein from the prokaryote Treponema denticola, encoded by TDE0597, has also been cloned and expressed in E. coli (Tucci et al., FEBS Lett, 581:1561-1566 (2007)). Six genes in Syntrophus aciditrophicus were identified by sequence homology to the C. acetobutylicum bcd gene product. The S. aciditrophicus genes syn_02637 and syn_02636 bear high sequence homology to the etfAB genes of C. acetobutylicum, and are predicted to encode the alpha and beta subunits of an electron transfer flavoprotein.

Protein GenBank ID GI Number Organism fadE AAC73325.2 87081702 Escherichia coli fadE YP_005241256.1 379699528 Salmonella enterica bcd NP_349317.1 15895968 Clostridium acetobutylicum etfA NP_349315.1 15895966 Clostridium acetobutylicum etfB NP_349316.1 15895967 Clostridium acetobutylicum TER Q5EU90.1 62287512 Euglena gracilis TER NP_612558.1 19924091 Rattus norvegicus TDE0597 NP_971211.1 42526113 Treponema denticola syn_02587 ABC76101 85721158 Syntrophus aciditrophicus syn_02586 ABC76100 85721157 Syntrophus aciditrophicus syn_01146 ABC76260 85721317 Syntrophus aciditrophicus syn_00480 ABC77899 85722956 Syntrophus aciditrophicus syn_02128 ABC76949 85722006 Syntrophus aciditrophicus syn_01699 ABC78863 85723920 Syntrophus aciditrophicus syn_02637 ABC78522.1 85723579 Syntrophus aciditrophicus syn_02636 ABC78523.1 85723580 Syntrophus aciditrophicus

Additional enoyl-CoA reductase enzyme candidates are found in organisms that degrade aromatic compounds. Rhodopseudomonas palustris, a model organism for benzoate degradation, has the enzymatic capability to degrade pimelate via beta-oxidation of pimeloyl-CoA. Adjacent genes in the pim operon, pimC and pimD, bear sequence homology to C. acetobutylicum bcd and are predicted to encode a flavin-containing pimeloyl-CoA dehydrogenase (Harrison et al., 151:727-736 (2005)). The genome of nitrogen-fixing soybean symbiont Bradyrhizobium japonicum also contains a pim operon composed of genes with high sequence similarity to pimC and pimD of R. palustris (Harrison and Harwood, Microbiology 151:727-736 (2005)).

Protein GenBank ID GI Number Organism pimC CAE29155 39650632 Rhodopseudomonas palustris pimD CAE29154 39650631 Rhodopseudomonas palustris pimC BAC53083 27356102 Bradyrhizobium japonicum pimD BAC53082 27356101 Bradyrhizobium japonicum

An additional candidate is 2-methyl-branched chain enoyl-CoA reductase (EC 1.3.1.52 and EC 1.3.99.12), an enzyme catalyzing the reduction of sterically hindered trans-enoyl-CoA substrates. This enzyme participates in branched-chain fatty acid synthesis in the nematode Ascaris suum and is capable of reducing a variety of linear and branched chain substrates including 2-methylvaleryl-CoA, 2-methylbutanoyl-CoA, 2-methylpentanoyl-CoA, octanoyl-CoA and pentanoyl-CoA (Duran et al., 268:22391-22396 (1993)). Two isoforms of the enzyme, encoded by genes acad1 and acad, have been characterized.

Protein GenBank ID GI Number Organism acad1 AAC48316.1 2407655 Ascaris suum acad AAA16096.1 347404 Ascaris suum

At least three mitochondrial enoyl-CoA reductase enzymes exist in E. gracilis and are applicable for use in the invention. Three mitochondrial enoyl-CoA reductase enzymes of E. gracilis (ECR1-3) exhibit different chain length preferences (Inui et al., European Journal of Biochemistry 142:121-126 (1984)), which is particularly useful for dictating the chain length of the desired fatty alcohol, fatty aldehyde or fatty acid products. EST's ELL00002199, ELL00002335, and ELL00002648, which are all annotated as mitochondrial trans-2-enoyl-CoA reductases, can be used to isolate these additional enoyl-CoA reductase genes by methods known in the art. Two ECR enzymes from rat liver microsomes also exhibit different substrate specificities (Nagi et al, Arch Biochem Biophys 226:50-64 (1983)). The sequences of these enzymes have not been identified to date. The Mycobacterium smegmatis enoyl-CoA reductase accepts acyl-CoA substrates of chain lengths between C10-C16 (Shimakata et al, J Biochem 89:1075-80 (1981)).

Enoyl-CoA reductases and their chain length specificities are shown in the table below.

Chain length Gene Organism C4-C6 ECR1 Euglena gracilis C6-C8 ECR3 Euglena gracilis C8-10  ECR2 Euglena gracilis  C8-C16 Long chain ECR Rattus norvegicus C10-C16 ECR Mycobacterium smegmatis  C2-C18 fadE Salmonella enterica

Step E. Acyl-CoA Reductase (Aldehyde Forming)

Reduction of an acyl-CoA to a fatty alcohol is catalyzed by either a single enzyme or pair of enzymes that exhibit acyl-CoA reductase and alcohol dehydrogenase activities. Acyl-CoA dehydrogenases that reduce an acyl-CoA to its corresponding aldehyde include fatty acyl-CoA reductase (EC 1.2.1.42, 1.2.1.50), succinyl-CoA reductase (EC 1.2.1.76), acetyl-CoA reductase, butyryl-CoA reductase and propionyl-CoA reductase (EC 1.2.1.3). Aldehyde forming acyl-CoA reductase enzymes with demonstrated activity on acyl-CoA, 3-hydroxyacyl-CoA and 3-oxoacyl-CoA substrates are known in the literature. Several acyl-CoA reductase enzymes are active on 3-hydroxyacyl-CoA substrates. For example, some butyryl-CoA reductases from Clostridial organisms, are active on 3-hydroxybutyryl-CoA and propionyl-CoA reductase of L. reuteri is active on 3-hydroxypropionyl-CoA. An enzyme for converting 3-oxoacyl-CoA substrates to their corresponding aldehydes is malonyl-CoA reductase. Enzymes in this class that demonstrate activity on enoyl-CoA substrates have not been identified to date. Specificity for a particular substrate can be refined using evolution or enzyme engineering methods known in the art.

Exemplary fatty acyl-CoA reductases enzymes are encoded by acr1 of Acinetobacter calcoaceticus (Reiser, Journal of Bacteriology 179:2969-2975 (1997)) and Acinetobacter sp. M-1 (Ishige et al., Appl. Environ. Microbiol. 68:1192-1195 (2002)). Two gene products from Mycobacterium tuberculosis accept longer chain fatty acyl-CoA substrates of length C16-C18 (Harminder Singh, U. Central Florida (2007)). Yet another fatty acyl-CoA reductase is LuxC of Photobacterium phosphoreum (Lee et al, Biochim Biohys Acta 1388:215-22 (1997)). Enzymes with succinyl-CoA reductase activity are encoded by sucD of Clostridium kluyveri (Sohling, J. Bacteriol. 178:871-880 (1996)) and sucD of P. gingivalis (Takahashi, J. Bacteriol 182:4704-4710 (2000)). Additional succinyl-CoA reductase enzymes participate in the 3-hydroxypropionate/4-hydroxybutyrate cycle of thermophilic archaea including Metallosphaera sedula (Berg et al., Science 318:1782-1786 (2007)) and Thermoproteus neutrophilus (Ramos-Vera et al., J Bacteriol, 191:4286-4297 (2009)). The M. sedula enzyme, encoded by Msed_0709, is strictly NADPH-dependent and also has malonyl-CoA reductase activity. The T. neutrophilus enzyme is active with both NADPH and NADH. The enzyme acylating acetaldehyde dehydrogenase in Pseudomonas sp, encoded by bphG, is yet another as it has been demonstrated to oxidize and acylate acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde and formaldehyde (Powlowski, J. Bacteriol. 175:377-385 (1993)). In addition to reducing acetyl-CoA to ethanol, the enzyme encoded by adhE in Leuconostoc mesenteroides has been shown to oxidize the branched chain compound isobutyraldehyde to isobutyryl-CoA (Kazahaya, J. Gen. Appl. Microbiol. 18:43-55 (1972); and Koo et al., Biotechnol Lett. 27:505-510 (2005)). Butyraldehyde dehydrogenase catalyzes a similar reaction, conversion of butyryl-CoA to butyraldehyde, in solventogenic organisms such as Clostridium saccharoperbutylacetonicum (Kosaka et al., Biosci Biotechnol Biochem., 71:58-68 (2007)). Exemplary propionyl-CoA reductase enzymes include pduP of Salmonella typhimurium LT2 (Leal, Arch. Microbiol. 180:353-361 (2003)) and eutE from E. coli (Skraly, WO Patent No. 2004/024876). The propionyl-CoA reductase of Salmonella typhimurium LT2, which naturally converts propionyl-CoA to propionaldehyde, also catalyzes the reduction of 5-hydroxyvaleryl-CoA to 5-hydroxypentanal (WO 2010/068953A2). The propionaldehyde dehydrogenase of Lactobacillus reuteri, PduP, has a broad substrate range that includes butyraldehyde, valeraldehyde and 3-hydroxypropionaldehyde (Luo et al, Appl Microbiol Biotech, 89: 697-703 (2011). Additionally, some acyl-ACP reductase enzymes such as the orf1594 gene product of Synechococcus elongatus PCC7942 also exhibit aldehyde-forming acyl-CoA reductase activity (Schirmer et al, Science, 329: 559-62 (2010)). Acyl-ACP reductase enzymes and homologs are described in further detail in Example IX.

Protein GenBank ID GI Number Organism acr1 YP_047869.1 50086359 Acinetobacter calcoaceticus acr1 AAC45217 1684886 Acinetobacter baylyi acr1 BAB85476.1 18857901 Acinetobacter sp. Strain M-1 Rv1543 NP_216059.1 15608681 Mycobacterium tuberculosis Rv3391 NP_217908.1 15610527 Mycobacterium tuberculosis LuxC AAT00788.1 46561111 Photobacterium phosphoreum Msed_(—) YP_001190808.1 146303492 Metallosphaera sedula 0709 Tneu_(—) ACB39369.1 170934108 Thermoproteus 0421 neutrophilus sucD P38947.1 172046062 Clostridium kluyveri sucD NP_904963.1 34540484 Porphyromonas gingivalis bphG BAA03892.1 425213 Pseudomonas sp adhE AAV66076.1 55818563 Leuconostoc mesenteroides bld AAP42563.1 31075383 Clostridium saccharoperbutylacetonicum pduP NP_460996 16765381 Salmonella typhimurium LT2 eutE NP_416950 16130380 Escherichia coli pduP CCC03595.1 337728491 Lactobacillus reuteri

An additional enzyme type that converts an acyl-CoA to its corresponding aldehyde is malonyl-CoA reductase which transforms malonyl-CoA to malonic semialdehyde. Malonyl-CoA reductase is a key enzyme in autotrophic carbon fixation via the 3-hydroxypropionate cycle in thermoacidophilic archaeal bacteria (Berg, Science 318:1782-1786 (2007); and Thauer, Science 318:1732-1733 (2007)). The enzyme utilizes NADPH as a cofactor and has been characterized in Metallosphaera and Sulfolobus sp. (Alber et al., J. Bacteriol. 188:8551-8559 (2006); and Hugler, J. Bacteriol. 184:2404-2410 (2002)). The enzyme is encoded by Msed_0709 in Metallosphaera sedula (Alber et al., J. Bacteriol. 188:8551-8559 (2006); and Berg, Science 318:1782-1786 (2007)). A gene encoding a malonyl-CoA reductase from Sulfolobus tokodaii was cloned and heterologously expressed in E. coli (Alber et al., J. Bacteriol 188:8551-8559 (2006). This enzyme has also been shown to catalyze the conversion of methylmalonyl-CoA to its corresponding aldehyde (WO2007141208 (2007)). Although the aldehyde dehydrogenase functionality of these enzymes is similar to the bifunctional dehydrogenase from Chloroflexus aurantiacus, there is little sequence similarity. Both malonyl-CoA reductase enzyme candidates have high sequence similarity to aspartate-semialdehyde dehydrogenase, an enzyme catalyzing the reduction and concurrent dephosphorylation of aspartyl-4-phosphate to aspartate semialdehyde. Additional gene candidates can be found by sequence homology to proteins in other organisms including Sulfolobus solfataricus and Sulfolobus acidocaldarius and have been listed below. Yet another candidate for CoA-acylating aldehyde dehydrogenase is the ald gene from Clostridium beijerinckii (Toth, Appl. Environ. Microbiol. 65:4973-4980 (1999). This enzyme has been reported to reduce acetyl-CoA and butyryl-CoA to their corresponding aldehydes. This gene is very similar to eutE that encodes acetaldehyde dehydrogenase of Salmonella typhimurium and E. coli (Toth, Appl. Environ. Microbiol. 65:4973-4980 (1999).

Gene GenBank ID GI Number Organism Msed_0709 YP_001190808.1 146303492 Metallosphaera sedula mcr NP_378167.1 15922498 Sulfolobus tokodaii asd-2 NP_343563.1 15898958 Sulfolobus solfataricus Saci_2370 YP_256941.1 70608071 Sulfolobus acidocaldarius Ald AAT66436 49473535 Clostridium beijerinckii eutE AAA80209 687645 Salmonella typhimurium eutE NP_416950 16130380 Escherichia coli

Chain length specificity ranges of selected aldehyde-forming acyl-CoA reductase enzymes are show in the table below.

Chain length Gene Organism C2-C4 bphG Pseudomonas sp C4 Bld Clostridium saccharoperbutylacetonicum C12-C20 ACR Acinetobacter calcoaceticus C14-C18 Acr1 Acinetobacter sp. Strain M-1 C16-C18 Rv1543, Rv3391 Mycobacterium tuberculosis

Step G. Acyl-CoA Reductase (Alcohol Forming)

Bifunctional alcohol-forming acyl-CoA reductase enzymes catalyze step G (i.e. step E and F) of FIGS. 1 and 6. Enzymes with this activity include adhE of E. coli (Kessler et al., FEBS. Lett. 281:59-63 (1991))) and adhE2 of Clostridium acetobutylicum (Fontaine et al., J. Bacteriol. 184:821-830 (2002))). The E. coli enzyme is active on C2 substrates, whereas the C. acetobutylicum enzyme has a broad substrate range that spans C2-C8 (Dekishima et al, J Am Chem Soc 133:11399-11401 (2011)). The C. acetobutylicum enzymes encoded by bdh I and bdh II (Walter, et al., J. Bacteriol. 174:7149-7158 (1992)), reduce acetyl-CoA and butyryl-CoA to ethanol and butanol, respectively. The adhE gene produce from Leuconostoc mesenteroides is active on acetyl-CoA and isobutyryl-CoA (Kazahaya et al., J. Gen. Appl. Microbiol. 18:43-55 (1972); Koo et al., Biotechnol Lett, 27:505-510 (2005)). Enzyme candidates in other organisms including Roseiflexus castenholzii, Erythrobacter sp. NAP1 and marine gamma proteobacterium HTCC2080 can be inferred by sequence similarity. Longer chain acyl-CoA molecules can be reduced to their corresponding alcohols by enzymes such as the jojoba (Simmondsia chinensis) FAR which encodes an alcohol-forming fatty acyl-CoA reductase. Its overexpression in E. coli resulted in FAR activity and the accumulation of C16-C18 fatty alcohols (Metz et al., Plant Physiol, 122:635-644 (2000)). FAR enzymes in Arabidopsis thaliana include the gene products of At3g11980 and At3g44560 (Doan et al, J Plant Physiol 166 (2006)). Bifunctional prokaryotic FAR enzymes are found in Marinobacter aquaeolei VT8 (Hofvander et al, FEBS Lett 3538-43 (2011)), Marinobacter algicola and Oceanobacter strain RED65 (US Pat Appl 20110000125). Other suitable enzymes include bfar from Bombyx mori, mfar1 and mfar2 from Mus musculus; mfar2 from Mus musculus; acrM1 from Acinetobacter sp. M1; and hfar from H. sapiens.

Protein GenBank ID GI Number Organism adhE NP_415757.1 16129202 Escherichia coli adhE2 AAK09379.1 12958626 Clostridium acetobutylicum bdh I NP_349892.1 15896543 Clostridium acetobutylicum bdh II NP_349891.1 15896542 Clostridium acetobutylicum adhE AAV66076.1 55818563 Leuconostoc mesenteroides mcr AAS20429.1 42561982 Chloroflexus aurantiacus Rcas_2929 YP_001433009.1 156742880 Roseiflexus castenholzii NAP1_02720 ZP_01039179.1 85708113 Erythrobacter sp. NAP1 MGP2080_00535 ZP_01626393.1 119504313 marine gamma proteobacterium HTCC2080 FAR AAD38039.1 5020215 Simmondsia chinensis At3g11980 NP_191229.1 15228993 Arabidopsis thaliana At3g44560 NP_190042.2 145339120 Arabidopsis thaliana FAR YP_959486.1 120555135 Marinobacter aquaeolei bfar Q8R079 81901336 Bombyx mori

Chain length specificity ranges of selected alcohol-forming acyl-CoA reductase enzymes are show in the table below.

Chain length Gene Organism C2  adhE Escherichia coli C2-C8 adhe2 Clostridium acetobutylicum C14-C16 At3g11980 Arabidopsis thaliana C16 At3g44560 Arabidopsis thaliana C16-C18 FAR Simmondsia chinensis C14-C18 FAR Marinobacter aquaeolei

Step F. Fatty Aldehyde Reductase

Exemplary genes encoding enzymes that catalyze the conversion of an aldehyde to alcohol (i.e., alcohol dehydrogenase or equivalently aldehyde reductase) include alrA encoding a medium-chain alcohol dehydrogenase for C2-C14 (Tani et al., Appl. Environ. Microbiol. 66:5231-5235 (2000)), yqhD and fucO from E. coli (Sulzenbacher et al., 342:489-502 (2004)), and bdh I and bdh II from C. acetobutylicum which converts butyryaldehyde into butanol (Walter et al., J Bacteriol 174:7149-7158 (1992)). The alrA gene product showed no activity on aldehydes longer than C14, and favored the reductive direction (Tani et al, supra). YqhD catalyzes the reduction of a wide range of aldehydes using NADPH as the cofactor, with a preference for chain lengths longer than C(3) (Sulzenbacher et al, J Mol Biol 342:489-502 (2004); Perez et al., J Biol. Chem. 283:7346-7353 (2008)). The adhA gene product from Zymomonas mobilis has been demonstrated to have activity on a number of aldehydes including formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and acrolein (Kinoshita et al., Appl Microbiol Biotechnol 22:249-254 (1985)). Additional aldehyde reductase candidates are encoded by bdh in C. saccharoperbutylacetonicum and Cbei_1722, Cbei_2181 and Cbei_2421 in C. beijerinckii. The alcohol dehydrogenase from Leifsonia sp. S749 shows maximal activity on medium chain-length substrates of length C6-C7 (Inoue et al, AEM 71: 3633-3641 (2005). The adh gene product of Pseudomonas putida is active on substrates of length C3-C10 (Nagashima et al, J Ferment Bioeng 82:328-33 (1996)). The alcohol dehydrogenase enzymes ADH1 and ADH2 of Geobacillus thermodenitrificans oxidize alcohols up to a chain length of C30 (Liu et al, Physiol Biochem 155:2078-85 (2009)).

Protein GenBank ID GI Number Organism alrA BAB12273.1 9967138 Acinetobacter sp. strain M-1 ADH2 NP_014032.1 6323961 Saccharomyces cerevisiae yqhD NP_417484.1 16130909 Escherichia coli fucO NP_417279.1 16130706 Escherichia coli bdh I NP_349892.1 15896543 Clostridium acetobutylicum bdh II NP_349891.1 15896542 Clostridium acetobutylicum adhA YP_162971.1 56552132 Zymomonas mobilis bdh BAF45463.1 124221917 Clostridium saccharoperbutylacetonicum Cbei_(—) YP_001308850 150016596 Clostridium beijerinckii 1722 Cbei_(—) YP_001309304 150017050 Clostridium beijerinckii 2181 Cbei_(—) YP_001309535 150017281 Clostridium beijerinckii 2421 lsadh BAD99642.1 67625613 Leifsonia sp. S749 adh Pseudomonas putida

Native alcohol dehydrogenases also convert aldehyde substrates to alcohol products. To date, seven alcohol dehydrogenases, ADHI-ADHVII, have been reported in S. cerevisiae (de Smidt et al, FEMS Yeast Res 8:967-78 (2008)). ADH1 (GI:1419926) is the key enzyme responsible for reducing acetaldehyde to ethanol in the cytosol under anaerobic conditions. In K. lactis, two NAD-dependent cytosolic alcohol dehydrogenases have been identified and characterized. These genes also show activity for other aliphatic alcohols. The genes ADH1 (GI:113358) and ADHII (GI:51704293) are preferentially expressed in glucose-grown cells (Bozzi et al, Biochim Biophys Acta 1339:133-142 (1997)). Cytosolic alcohol dehydrogenases are encoded by ADH1 (GI:608690) in C. albicans, ADH1 (GI:3810864) in S. pombe, ADH1 (GI:5802617) in Y. lipolytica, ADH1 (GI:2114038) and ADHII (GI:2143328) in Pichia stipitis or Scheffersomyces stipitis (Passoth et al, Yeast 14:1311-23 (1998)). Candidate alcohol dehydrogenases are shown the table below.

Protein GenBank ID GI number Organism SADH BAA24528.1 2815409 Candida parapsilosis ADH1 NP_014555.1 6324486 Saccharomyces cerevisiae s288c ADH2 NP_014032.1 6323961 Saccharomyces cerevisiae s288c ADH3 NP_013800.1 6323729 Saccharomyces cerevisiae s288c ADH4 NP_011258.2 269970305 Saccharomyces cerevisiae s288c ADH5 NP_010113.1 6320033 Saccharomyces cerevisiae (SFA1) s288c ADH6 NP_014051.1 6323980 Saccharomyces cerevisiae s288c ADH7 NP_010030.1 6319949 Saccharomyces cerevisiae s288c adhP CAA44614.1 2810 Kluyveromyces lactis ADH1 P20369.1 113358 Kluyveromyces lactis ADH2 CAA45739.1 2833 Kluyveromyces lactis ADH3 P49384.2 51704294 Kluyveromyces lactis ADH1 YP_001126968.1 138896515 Geobacillus thermodenitrificans ADH2 YP_001125863.1 138895410 Geobacillus thermodenitrificans

Substrate specificity ranges of selected alcohol dehydrogenase enzymes are show in the table below.

Chain length Gene Organism C6-C7  lsadh Leifsonia sp. S749 C2-C8  yqhD Escherichia coli C3-C10 Adh Pseudomonas putida C2-C14 alrA Acinetobacter sp. strain M-1 C2-C30 ADH1 Geobacillus thermodenitrificans

Those skilled in the art also can obtain nucleic acids encoding any or all of the malonyl-CoA independent FAS pathway or acyl-reduction pathway enzymes by cloning using known sequences from available sources. For example, any or all of the encoding nucleic acids for the malonyl-CoA independent FAS pathway can be readily obtained using methods well known in the art from E. gracilis as this pathway has been well characterized in this organism. E. gracilis encoding nucleic acids can be isolated from, for example, an E. gracilis cDNA library using probes of known sequence. The probes can be designed with whole or partial DNA sequences from the following EST sequences from the publically available sequence database TBestDB (http://tbestdb.bcm.umontreal.ca). The nucleic acids generated from this process can be inserted into an appropriate expression vector and transformed into E. coli or other microorganisms to generate fatty alcohols, fatty aldehydes or fatty acids production organisms of the invention.

-   -   Thiolase (FIG. 1A): ELL00002550, ELL00002493, ELL00000789     -   3-Hydroxyacyl-CoA dehydrogenase (FIG. 1B): ELL00000206,         ELL00002419, ELL00006286, ELL00006656     -   Enoyl-CoA hydratase (FIG. 1C): ELL00005926, ELL00001952,         ELL00002235, ELL00006206     -   Enoyl-CoA reductase (FIG. 1D): ELL00002199, ELL00002335,         ELL00002648     -   Acyl-CoA reductase (FIG. 1E; 1E/F): ELL00002572, ELL00002581,         ELL00000108

Alternatively, the above EST sequences can be used to identify homologue polypeptides in GenBank through BLAST search. The resulting homologue polypeptides and their corresponding gene sequences provide additional encoding nucleic acids for transformation into E. coli or other microorganisms to generate the fatty alcohols, fatty aldehydes or fatty acids producing organisms of the invention. Listed below are exemplary homologue polypeptide and their gene accession numbers in GenBank which are applicable for use in the non-naturally occurring organisms of the invention.

Ketoacyl-CoA acyltransferase (or ketoacyl-CoA thiolase)

Protein GenBank ID GI number Organism Dole_2160 YP_001530041 158522171 Desulfococcus oleovorans Hxd3 DalkDRAFT_(—) ZP_02133627 163726110 Desulfatibacillum 1939 alkenivorans AK-01 BSG1_09488 ZP_01860900 149182424 Bacillus sp. SG-1

3-Hydroxyacyl-CoA dehydrogenase

Protein GenBank ID GI number Organism AaeL_AAEL002841 XP_001655993 157132312 Aedes aegypti hadh NP_001011073 58331907 Xenopus tropicalis hadh NP_001003515 51011113 Danio rerio

Enoyl-CoA hydratase

Protein GenBank ID GI number Organism Tb927.3.4850 XP_844077 72387305 Trypano- soma brucei Tc00.1047053509701.10 XP_802711 71399112 Trypano- soma cruzi strain CL Brener PputGB1_3629 YP_001669856 167034625 Pseudo- monas putida GB-1

Enoyl-CoA reductase

Protein GenBank ID GI number Organism mecr XP_642118 66816217 Dictyostelium discoideum AX4 NEMVEDRAFT_(—) XP_001639469 156402181 Nematostella v1g228294 vectensis AaeL_AAEL003995 XP_001648220 157104018 Aedes aegypti

In addition to the above exemplary encoding nucleic acids, nucleic acids other than those within the MI-FAE cycle and/or termination pathways of the invention also can be introduced into a host organism for further production of fatty alcohols, fatty aldehydes or fatty acids. For example, the Ralstonia eutropha BktB and PhbB genes catalyze the condensation of butyryl-CoA and acetyl-CoA to form β-keto-hexanoyl-CoA and the reduction of β-keto-hexanoyl-CoA to 3-hydroxy-hexanoyl-CoA (Fukui et al., Biomacromolecules 3:618-624 (2002)). To improve the production of fatty alcohols, exogenous DNA sequences encoding for these specific enzymes can be expressed in the production host of interest. Furthermore, the above described enzymes can be subjected to directed evolution to generate improved versions of these enzymes with high activity and high substrate specificity. A similar approach also can be utilized with any or all other enzymatic steps in the fatty alcohol, fatty aldehyde or fatty acid producing pathways of the invention to, for example, improve enzymatic activity and/or specificity and/or to generate a fatty alcohol, a fatty aldehyde or a fatty acid of a predetermined chain length or lengths.

Example II Pathways For Producing Cytosolic Acetyl-CoA from Cytosolic Pyruvate

The following example describes exemplary pathways for the conversion of cytosolic pyruvate and threonine to cytosolic acetyl-CoA, as shown in FIG. 2.

Pathways for the conversion of cytosolic pyruvate and threonine to cytosolic acetyl-CoA could enable deployment of a cytosolic fatty alcohol, fatty aldehyde or fatty acid production pathway that originates from acetyl-CoA. Several pathways for converting cytosolic pyruvate to cytosolic acetyl-CoA are shown in FIG. 2. Direct conversion of pyruvate to acetyl-CoA can be catalyzed by pyruvate dehydrogenase, pyruvate formate lyase, pyruvate:NAD(P) oxidoreductase or pyruvate:ferredoxin oxidoreductase. If a pyruvate formate lyase is utilized, the formate byproduct can be further converted to CO2 by formate dehydrogenase or formate hydrogen lyase.

Indirect conversion of pyruvate to acetyl-CoA can proceed through several alternate routes. Pyruvate can be converted to acetaldehyde by a pyruvate decarboxylase. Acetaldehyde can then converted to acetyl-CoA by an acylating (CoA-dependent) acetaldehyde dehydrogenase. Alternately, acetaldehyde generated by pyruvate decarboxylase can be converted to acetyl-CoA by the “PDH bypass” pathway. In this pathway, acetaldehyde is oxidized by acetaldehyde dehydrogenase to acetate, which is then converted to acetyl-CoA by a CoA ligase, synthetase or transferase. In another embodiment, the acetate intermediate is converted by an acetate kinase to acetyl-phosphate that is then converted to acetyl-CoA by a phosphotransacetylase. In yet another embodiment, pyruvate is directly converted to acetyl-phosphate by a pyruvate oxidase (acetyl-phosphate forming). Conversion of pyruvate to acetate is also catalyzed by acetate-forming pyruvate oxidase.

Cytosolic acetyl-CoA can also be synthesized from threonine by expressing a native or heterologous threonine aldolase (FIG. 5J) (van Maris et al, AEM 69:2094-9 (2003)). Threonine aldolase converts threonine into acetaldehyde and glycine. The acetaldehyde product is subsequently converted to acetyl-CoA by various pathways described above.

Gene candidates for the acetyl-CoA forming enzymes shown in FIG. 2 are described below.

Pyruvate oxidase (acetate-forming) (FIG. 2A) or pyruvate:quinone oxidoreductase (PQO) can catalyze the oxidative decarboxylation of pyruvate into acetate, using ubiquione (EC 1.2.5.1) or quinone (EC 1.2.2.1) as an electron acceptor. The E. coli enzyme, PoxB, is localized on the inner membrane (Abdel-Hamid et al., Microbiol 147:1483-98 (2001)). The enzyme has thiamin pyrophosphate and flavin adenine dinucleotide (FAD) cofactors (Koland and Gennis, Biochemistry 21:4438-4442 (1982)); O'Brien et al., Biochemistry 16:3105-3109 (1977); O'Brien and Gennis, J. Biol. Chem. 255:3302-3307 (1980)). PoxB has similarity to pyruvate decarboxylase of S. cerevisiae and Zymomonas mobilis. The pqo transcript of Corynebacterium glutamicum encodes a quinone-dependent and acetate-forming pyruvate oxidoreductase (Schreiner et al., J Bacteriol 188:1341-50 (2006)). Similar enzymes can be inferred by sequence homology.

Protein GenBank ID GI Number Organism poxB NP_415392.1 16128839 Escherichia coli pqo YP_226851.1 62391449 Corynebacterium glutamicum poxB YP_309835.1 74311416 Shigella sonnei poxB ZP_03065403.1 194433121 Shigella dysenteriae

The acylation of acetate to acetyl-CoA (FIG. 2B) can be catalyzed by enzymes with acetyl-CoA synthetase, ligase or transferase activity. Two enzymes that can catalyze this reaction are AMP-forming acetyl-CoA synthetase or ligase (EC 6.2.1.1) and ADP-forming acetyl-CoA synthetase (EC 6.2.1.13). AMP-forming acetyl-CoA synthetase (ACS) is the predominant enzyme for activation of acetate to acetyl-CoA. Exemplary ACS enzymes are found in E. coli (Brown et al., J. Gen. Microbiol. 102:327-336 (1977)), Ralstonia eutropha (Priefert and Steinbuchel, J. Bacteriol. 174:6590-6599 (1992)), Methanothermobacter thermautotrophicus (Ingram-Smith and Smith, Archaea 2:95-107 (2007)), Salmonella enterica (Gulick et al., Biochemistry 42:2866-2873 (2003)) and Saccharomyces cerevisiae (Jogl and Tong, Biochemistry 43:1425-1431 (2004)). ADP-forming acetyl-CoA synthetases are reversible enzymes with a generally broad substrate range (Musfeldt and Schonheit, J. Bacteriol. 184:636-644 (2002)). Two isozymes of ADP-forming acetyl-CoA synthetases are encoded in the Archaeoglobus fulgidus genome by are encoded by AF1211 and AF1983 (Musfeldt and Schonheit, supra (2002)). The enzyme from Haloarcula marismortui (annotated as a succinyl-CoA synthetase) also accepts acetate as a substrate and reversibility of the enzyme was demonstrated (Brasen and Schonheit, Arch. Microbiol. 182:277-287 (2004)). The ACD encoded by PAE3250 from hyperthermophilic crenarchaeon Pyrobaculum aerophilum showed the broadest substrate range of all characterized ACDs, reacting with acetate, isobutyryl-CoA (preferred substrate) and phenylacetyl-CoA (Brasen and Schonheit, supra (2004)). Directed evolution or engineering can be used to modify this enzyme to operate at the physiological temperature of the host organism. The enzymes from A. fulgidus, H. marismortui and P. aerophilum have all been cloned, functionally expressed, and characterized in E. coli (Brasen and Schonheit, supra (2004); Musfeldt and Schonheit, supra (2002)). Additional candidates include the succinyl-CoA synthetase encoded by sucCD in E. coli (Buck et al., Biochemistry 24:6245-6252 (1985)) and the acyl-CoA ligase from Pseudomonas putida (Fernandez-Valverde et al., Appl. Environ. Microbiol. 59:1149-1154 (1993)). The aforementioned proteins are shown below.

Protein GenBank ID GI Number Organism acs AAC77039.1 1790505 Escherichia coli acoE AAA21945.1 141890 Ralstonia eutropha acs1 ABC87079.1 86169671 Methanothermobacter thermautotrophicus acs1 AAL23099.1 16422835 Salmonella enterica ACS1 Q01574.2 257050994 Saccharomyces cerevisiae AF1211 NP_070039.1 11498810 Archaeoglobus fulgidus AF1983 NP_070807.1 11499565 Archaeoglobus fulgidus scs YP_135572.1 55377722 Haloarcula marismortui PAE3250 NP_560604.1 18313937 Pyrobaculum aerophilum str. IM2 sucC NP_415256.1 16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia coli paaF AAC24333.2 22711873 Pseudomonas putida

The acylation of acetate to acetyl-CoA can also be catalyzed by CoA transferase enzymes (FIG. 2B). Numerous enzymes employ acetate as the CoA acceptor, resulting in the formation of acetyl-CoA. An exemplary CoA transferase is acetoacetyl-CoA transferase, encoded by the E. coli atoA (alpha subunit) and atoD (beta subunit) genes (Korolev et al., Acta Crystallogr. D. Biol. Crystallogr. 58:2116-2121 (2002); Vanderwinkel et al., 33:902-908 (1968)). This enzyme has a broad substrate range (Sramek et al., Arch Biochem Biophys 171:14-26 (1975)) and has been shown to transfer the CoA moiety to acetate from a variety of branched and linear acyl-CoA substrates, including isobutyrate (Matthies et al., Appl Environ. Microbiol 58:1435-1439 (1992)), valerate (Vanderwinkel et al., Biochem. Biophys. Res. Commun. 33:902-908 (1968)) and butanoate (Vanderwinkel et al., Biochem. Biophys. Res. Commun. 33:902-908 (1968)). Similar enzymes exist in Corynebacterium glutamicum ATCC 13032 (Duncan et al., 68:5186-5190 (2002)), Clostridium acetobutylicum (Cary et al., Appl Environ Microbiol 56:1576-1583 (1990); Wiesenborn et al., Appl Environ Microbiol 55:323-329 (1989)), and Clostridium saccharoperbutylacetonicum (Kosaka et al., Biosci. Biotechnol Biochem. 71:58-68 (2007)).

Gene GI # Accession No. Organism atoA 2492994 P76459.1 Escherichia coli atoD 2492990 P76458.1 Escherichia coli actA 62391407 YP_226809.1 Corynebacterium glutamicum cg0592 62389399 YP_224801.1 Corynebacterium glutamicum ctfA 15004866 NP_149326.1 Clostridium acetobutylicum ctfB 15004867 NP_149327.1 Clostridium acetobutylicum ctfA 31075384 AAP42564.1 Clostridium saccharoperbutylacetonicum ctfB 31075385 AAP42565.1 Clostridium saccharoperbutylacetonicum

Acetate kinase (EC 2.7.2.1) can catalyzes the reversible ATP-dependent phosphorylation of acetate to acetylphosphate (FIG. 2C). Exemplary acetate kinase enzymes have been characterized in many organisms including E. coli, Clostridium acetobutylicum and Methanosarcina thermophila (Ingram-Smith et al., J. Bacteriol. 187:2386-2394 (2005); Fox and Roseman, J. Biol. Chem. 261:13487-13497 (1986); Winzer et al., Microbioloy 143 (Pt 10):3279-3286 (1997)). Acetate kinase activity has also been demonstrated in the gene product of E. coli purT (Marolewski et al., Biochemistry 33:2531-2537 (1994). Some butyrate kinase enzymes (EC 2.7.2.7), for example buk1 and buk2 from Clostridium acetobutylicum, also accept acetate as a substrate (Hartmanis, M. G., J. Biol. Chem. 262:617-621 (1987)). Homologs exist in several other organisms including Salmonella enterica and Chlamydomonas reinhardtii.

Protein GenBank ID GI Number Organism ackA NP_416799.1 16130231 Escherichia coli Ack AAB18301.1 1491790 Clostridium acetobutylicum Ack AAA72042.1 349834 Methanosarcina thermophila purT AAC74919.1 1788155 Escherichia coli buk1 NP_349675 15896326 Clostridium acetobutylicum buk2 Q97II1 20137415 Clostridium acetobutylicum ackA NP_461279.1 16765664 Salmonella typhimurium ACK1 XP_001694505.1 159472745 Chlamydomonas reinhardtii ACK2 XP_001691682.1 159466992 Chlamydomonas reinhardtii

The formation of acetyl-CoA from acetyl-phosphate can be catalyzed by phosphotransacetylase (EC 2.3.1.8) (FIG. 2D). The pta gene from E. coli encodes an enzyme that reversibly converts acetyl-CoA into acetyl-phosphate (Suzuki, T., Biochim. Biophys. Acta 191:559-569 (969)). Additional acetyltransferase enzymes have been characterized in Bacillus subtilis (Rado and Hoch, Biochim. Biophys. Acta 321:114-125 (1973), Clostridium kluyveri (Stadtman, E., Methods Enzymol. 1:5896-599 (1955), and Thermotoga maritima (Bock et al., J. Bacteriol. 181:1861-1867 (1999)). This reaction can also be catalyzed by some phosphotranbutyrylase enzymes (EC 2.3.1.19), including the ptb gene products from Clostridium acetobutylicum (Wiesenborn et al., App. Environ. Microbiol. 55:317-322 (1989); Walter et al., Gene 134:107-111 (1993)). Additional ptb genes are found in butyrate-producing bacterium L2-50 (Louis et al., J. Bacteriol. 186:2099-2106 (2004) and Bacillus megaterium (Vazquez et al., Curr. Microbiol. 42:345-349 (2001). Homologs to the E. coli pta gene exist in several other organisms including Salmonella enterica and Chlamydomonas reinhardtii.

Protein GenBank ID GI Number Organism Pta NP_416800.1 71152910 Escherichia coli Pta P39646 730415 Bacillus subtilis Pta A5N801 146346896 Clostridium kluyveri Pta Q9X0L4 6685776 Thermotoga maritime Ptb NP_349676 34540484 Clostridium acetobutylicum Ptb AAR19757.1 38425288 butyrate-producing bacterium L2-50 Ptb CAC07932.1 10046659 Bacillus megaterium Pta NP_461280.1 16765665 Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 PAT2 XP_001694504.1 159472743 Chlamydomonas reinhardtii PAT1 XP_001691787.1 159467202 Chlamydomonas reinhardtii

Pyruvate decarboxylase (PDC) is a key enzyme in alcoholic fermentation, catalyzing the decarboxylation of pyruvate to acetaldehyde (FIG. 2E). The PDC 1 enzyme from Saccharomyces cerevisiae has been extensively studied (Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001); Li et al., Biochemistry. 38:10004-10012 (1999); ter Schure et al., Appl. Environ. Microbiol. 64:1303-1307 (1998)). Other well-characterized PDC enzymes are found in Zymomonas mobilus (Siegert et al., Protein Eng Des Sel 18:345-357 (2005)), Acetobacter pasteurians (Chandra et al., 176:443-451 (2001)) and Kluyveromyces lactis (Krieger et al., 269:3256-3263 (2002)). The PDC1 and PDC5 enzymes of Saccharomyces cerevisiae are subject to positive transcriptional regulation by PDC2 (Hohmann et al, Mol Gen Genet. 241:657-66 (1993)). Pyruvate decarboxylase activity is also possessed by a protein encoded by CTRG_03826 (GI:255729208) in Candida tropicalis, PDC1 (GI number: 1226007) in Kluyveromyces lactis, YALI0D10131g (GI:50550349) in Yarrowia lipolytica, PAS_chr3_0188 (GI:254570575) in Pichia pastoris, pyruvate decarboxylase (GI: GI:159883897) in Schizosaccharomyces pombe, ANI_1_1024084 (GI:145241548), ANI_1_796114 (GI:317034487), ANI_1_936024 (GI:317026934) and ANI_1_2276014 (GI:317025935) in Aspergillus niger.

Protein GenBank ID GI Number Organism pdc P06672.1 118391 Zymomonas mobilis pdc1 P06169 30923172 Saccharomyces cerevisiae Pdc2 NP_010366.1 6320286 Saccharomyces cerevisiae Pdc5 NP_013235.1 6323163 Saccharomyces cerevisiae CTRG_03826 XP_002549529 255729208 Candida tropicalis, CU329670.1: CAA90807 159883897 Schizosaccharo- 585597.587312 myces pombe YALI0D10131g XP_502647 50550349 Yarrowia lipolytica PAS_chr3_0188 XP_002492397 254570575 Pichia pastoris pdc Q8L388 20385191 Acetobacter pasteurians pdc1 Q12629 52788279 Kluyveromyces lactis ANI_1_1024084 XP_001393420 145241548 Aspergillus niger ANI_1_796114 XP_001399817 317026934 Aspergillus niger ANI_1_936024 XP_001396467 317034487 Aspergillus niger ANI_1_2276014 XP_001388598 317025935 Aspergillus niger

Aldehyde dehydrogenase enzymes in EC class 1.2.1 catalyze the oxidation of acetaldehyde to acetate (FIG. 2F). Exemplary genes encoding this activity were described above. The oxidation of acetaldehyde to acetate can also be catalyzed by an aldehyde oxidase with acetaldehyde oxidase activity. Such enzymes can convert acetaldehyde, water and O₂ to acetate and hydrogen peroxide. Exemplary aldehyde oxidase enzymes that have been shown to catalyze this transformation can be found in Bos taurus and Mus musculus (Garattini et al., Cell Mol Life Sci 65:1019-48 (2008); Cabre et al., Biochem Soc Trans 15:882-3 (1987)). Additional aldehyde oxidase gene candidates include the two flavin- and molybdenum-containing aldehyde oxidases of Zea mays, encoded by zmAO-1 and zmAO-2 (Sekimoto et al., J Biol Chem 272:15280-85 (1997)).

GenBank Gene Accession No. GI No. Organism zmAO-1 NP_001105308.1 162458742 Zea mays zmAO-2 BAA23227.1 2589164 Zea mays Aox1 O54754.2 20978408 Mus musculus XDH DAA24801.1 296482686 Bos taurus

Pyruvate oxidase (acetyl-phosphate forming) can catalyze the conversion of pyruvate, oxygen and phosphate to acetyl-phosphate and hydrogen peroxide (FIG. 2G). This type of pyruvate oxidase is soluble and requires the cofactors thiamin diphosphate and flavin adenine dinucleotide (FAD). Acetyl-phosphate forming pyruvate oxidase enzymes can be found in lactic acid bacteria Lactobacillus delbrueckii and Lactobacillus plantarum (Lorquet et al., J Bacteriol 186:3749-3759 (2004); Hager et al., Fed Proc 13:734-38 (1954)). A crystal structure of the L. plantarum enzyme has been solved (Muller et al., (1994)). In Streptococcus sanguinis and Streptococcus pneumonia, acetyl-phosphate forming pyruvate oxidase enzymes are encoded by the spxB gene (Spellerberg et al., Mol Micro 19:803-13 (1996); Ramos-Montanez et al., Mol Micro 67:729-46 (2008)). The SpxR was shown to positively regulate the transcription of spxB in S. pneumoniae (Ramos-Montanez et al., supra). A similar regulator in S. sanguinis was identified by sequence homology. Introduction or modification of catalase activity can reduce accumulation of the hydrogen peroxide product.

GenBank Gene Accession No. GI No. Organism poxB NP_786788.1 28379896 Lactobacillus plantarum spxB L39074.1 1161269 Streptococcus pneumoniae Spd_0969 YP_816445.1 116517139 Streptococcus (spxR) pneumoniae spxB ZP_07887723.1 315612812 Streptococcus sanguinis spxR ZP_07887944.1 GI: 315613033 Streptococcus sanguinis

The pyruvate dehydrogenase (PDH) complex catalyzes the conversion of pyruvate to acetyl-CoA (FIG. 2H). The E. coli PDH complex is encoded by the genes aceEF and lpdA. Enzyme engineering efforts have improved the E. coli PDH enzyme activity under anaerobic conditions (Kim et al., J. Bacteriol. 190:3851-3858 (2008); Kim et al., Appl. Environ. Microbiol. 73:1766-1771 (2007); Zhou et al., Biotechnol. Lett. 30:335-342 (2008)). In contrast to the E. coli PDH, the B. subtilis complex is active and required for growth under anaerobic conditions (Nakano et al., 179:6749-6755 (1997)). The Klebsiella pneumoniae PDH, characterized during growth on glycerol, is also active under anaerobic conditions (Menzel et al., 56:135-142 (1997)). Crystal structures of the enzyme complex from bovine kidney (Zhou et al., 98:14802-14807 (2001)) and the E2 catalytic domain from Azotobacter vinelandii are available (Mattevi et al., Science. 255:1544-1550 (1992)). Some mammalian PDH enzymes complexes can react on alternate substrates such as 2-oxobutanoate. Comparative kinetics of Rattus norvegicus PDH and BCKAD indicate that BCKAD has higher activity on 2-oxobutanoate as a substrate (Paxton et al., Biochem. J. 234:295-303 (1986)). The S. cerevisiae PDH complex canconsist of an E2 (LAT1) core that binds E1 (PDA1, PDB1), E3 (LPD1), and Protein X (PDX1) components (Pronk et al., Yeast 12:1607-1633 (1996)). The PDH complex of S. cerevisiae is regulated by phosphorylation of E1 involving PKP1 (PDH kinase I), PTC5 (PDH phosphatase I), PKP2 and PTC6. Modification of these regulators may also enhance PDH activity. Coexpression of lipoyl ligase (LplA of E. coli and AIM22 in S. cerevisiae) with PDH in the cytosol may be necessary for activating the PDH enzyme complex. Increasing the supply of cytosolic lipoate, either by modifying a metabolic pathway or media supplementation with lipoate, may also improve PDH activity.

Gene Accession No. GI Number Organism aceE NP_414656.1 16128107 Escherichia coli aceF NP_414657.1 16128108 Escherichia coli lpd NP_414658.1 16128109 Escherichia coli lplA NP_418803.1 16132203 Escherichia coli pdhA P21881.1 3123238 Bacillus subtilis pdhB P21882.1 129068 Bacillus subtilis pdhC P21883.2 129054 Bacillus subtilis pdhD P21880.1 118672 Bacillus subtilis aceE YP_001333808.1 152968699 Klebsiella pneumoniae aceF YP_001333809.1 152968700 Klebsiella pneumoniae lpdA YP_001333810.1 152968701 Klebsiella pneumoniae Pdha1 NP_001004072.2 124430510 Rattus norvegicus Pdha2 NP_446446.1 16758900 Rattus norvegicus Dlat NP_112287.1 78365255 Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus LAT1 NP_014328 6324258 Saccharomyces cerevisiae PDA1 NP_011105 37362644 Saccharomyces cerevisiae PDB1 NP_009780 6319698 Saccharomyces cerevisiae LPD1 NP_116635 14318501 Saccharomyces cerevisiae PDX1 NP_011709 6321632 Saccharomyces cerevisiae AIM22 NP_012489.2 83578101 Saccharomyces cerevisiae

As an alternative to the large multienzyme PDH complexes described above, some organisms utilize enzymes in the 2-ketoacid oxidoreductase family (OFOR) to catalyze acylating oxidative decarboxylation of 2-keto-acids. Unlike the PDH complexes, PFOR enzymes contain iron-sulfur clusters, utilize different cofactors and use ferredoxin or flavodixin as electron acceptors in lieu of NAD(P)H. Pyruvate ferredoxin oxidoreductase (PFOR) can catalyze the oxidation of pyruvate to form acetyl-CoA (FIG. 2H). The PFOR from Desulfovibrio africanus has been cloned and expressed in E. coli resulting in an active recombinant enzyme that was stable for several days in the presence of oxygen (Pieulle et al., J Bacteriol. 179:5684-5692 (1997)). Oxygen stability is relatively uncommon in PFORs and is believed to be conferred by a 60 residue extension in the polypeptide chain of the D. africanus enzyme. The M. thermoacetica PFOR is also well characterized (Menon et al., Biochemistry 36:8484-8494 (1997)) and was even shown to have high activity in the direction of pyruvate synthesis during autotrophic growth (Furdui et al., J Biol. Chem. 275:28494-28499 (2000)). Further, E. coli possesses an uncharacterized open reading frame, ydbK, that encodes a protein that is 51% identical to the M. thermoacetica PFOR. Evidence for pyruvate oxidoreductase activity in E. coli has been described (Blaschkowski et al., Eur. J Biochem. 123:563-569 (1982)). Several additional PFOR enzymes are described in Ragsdale, Chem. Rev. 103:2333-2346 (2003). Finally, flavodoxin reductases (e.g., fqrB from Helicobacter pylori or Campylobacter jejuni (St Maurice et al., J. Bacteriol. 189:4764-4773 (2007))) or Rnf-type proteins (Seedorf et al., Proc. Natl. Acad. Sci. U.S.A. 105:2128-2133 (2008); Herrmann et al., J. Bacteriol. 190:784-791 (2008)) provide a means to generate NADH or NADPH from the reduced ferredoxin generated by PFOR. These proteins are identified below.

Protein GenBank ID GI Number Organism Por CAA70873.1 1770208 Desulfovibrio africanus Por YP_428946.1 83588937 Moorella thermoacetica ydbK NP_415896.1 16129339 Escherichia coli fqrB NP_207955.1 15645778 Helicobacter pylori fqrB YP_001482096.1 157414840 Campylobacter jejuni RnfC EDK33306.1 146346770 Clostridium kluyveri RnfD EDK33307.1 146346771 Clostridium kluyveri RnfG EDK33308.1 146346772 Clostridium kluyveri RnfE EDK33309.1 146346773 Clostridium kluyveri RnfA EDK33310.1 146346774 Clostridium kluyveri RnfB EDK33311.1 146346775 Clostridium kluyveri

Pyruvate formate-lyase (PFL, EC 2.3.1.54) (FIG. 2H), encoded by pflB in E. coli, can convert pyruvate into acetyl-CoA and formate. The activity of PFL can be enhanced by an activating enzyme encoded by pflA (Knappe et al., Proc. Natl. Acad. Sci U.S.A. 81:1332-1335 (1984); Wong et al., Biochemistry 32:14102-14110 (1993)). Keto-acid formate-lyase (EC 2.3.1.-), also known as 2-ketobutyrate formate-lyase (KFL) and pyruvate formate-lyase 4, is the gene product of tdcE in E. coli. This enzyme catalyzes the conversion of 2-ketobutyrate to propionyl-CoA and formate during anaerobic threonine degradation, and can also substitute for pyruvate formate-lyase in anaerobic catabolism (Simanshu et al., J Biosci. 32:1195-1206 (2007)). The enzyme is oxygen-sensitive and, like PflB, can require post-translational modification by PFL-AE to activate a glycyl radical in the active site (Hesslinger et al., Mol. Microbiol 27:477-492 (1998)). A pyruvate formate-lyase from Archaeoglobus fulgidus encoded by pflD has been cloned, expressed in E. coli and characterized (Lehtio et al., Protein Eng Des Sel 17:545-552 (2004)). The crystal structures of the A. fulgidus and E. coli enzymes have been resolved (Lehtio et al., J Mol. Biol. 357:221-235 (2006); Leppanen et al., Structure. 7:733-744 (1999)). Additional PFL and PFL-AE candidates are found in Lactococcus lactis (Melchiorsen et al., Appl Microbiol Biotechnol 58:338-344 (2002)), and Streptococcus mutans (Takahashi-Abbe et al., Oral. Microbiol Immunol. 18:293-297 (2003)), Chlamydomonas reinhardtii (Hemschemeier et al., Eukaryot. Cell 7:518-526 (2008b); Atteia et al., J. Biol. Chem. 281:9909-9918 (2006)) and Clostridium pasteurianum (Weidner et al., J Bacteriol. 178:2440-2444 (1996)).

Protein GenBank ID GI Number Organism pflB NP_415423 16128870 Escherichia coli pflA NP_415422.1 16128869 Escherichia coli tdcE AAT48170.1 48994926 Escherichia coli pflD NP_070278.1 11499044 Archaeoglobus fulgidus pfl CAA03993 2407931 Lactococcus lactis pfl BAA09085 1129082 Streptococcus mutans PFL1 XP_001689719.1 159462978 Chlamydomonas reinhardtii pflA1 XP_001700657.1 159485246 Chlamydomonas reinhardtii pfl Q46266.1 2500058 Clostridium pasteurianum act CAA63749.1 1072362 Clostridium pasteurianum

If a pyruvate formate lyase is utilized to convert pyruvate to acetyl-CoA, coexpression of a formate dehydrogenase or formate hydrogen lyase enzyme will converte formate to carbon dioxide. Formate dehydrogenase (FDH) catalyzes the reversible transfer of electrons from formate to an acceptor. Enzymes with FDH activity utilize various electron carriers such as, for example, NADH (EC 1.2.1.2), NADPH (EC 1.2.1.43), quinols (EC 1.1.5.6), cytochromes (EC 1.2.2.3) and hydrogenases (EC 1.1.99.33). FDH enzymes have been characterized from Moorella thermoacetica (Andreesen and Ljungdahl, J Bacteriol 116:867-873 (1973); Li et al., J Bacteriol 92:405-412 (1966); Yamamoto et al., J Biol Chem. 258:1826-1832 (1983). The loci, Moth_2312 is responsible for encoding the alpha subunit of formate dehydrogenase while the beta subunit is encoded by Moth_2314 (Pierce et al., Environ Microbiol (2008)). Another set of genes encoding formate dehydrogenase activity with a propensity for CO₂ reduction is encoded by Sfum_2703 through Sfum_2706 in Syntrophobacter fumaroxidans (de Bok et al., Eur J Biochem. 270:2476-2485 (2003)); Reda et al., PNAS 105:10654-10658 (2008)). A similar set of genes presumed to carry out the same function are encoded by CHY_0731, CHY_0732, and CHY_0733 in C. hydrogenoformans (Wu et al., PLoS Genet. 1:e65 (2005)). Formate dehydrogenases are also found many additional organisms including C. carboxidivorans P7, Bacillus methanolicus, Burkholderia stabilis, Moorella thermoacetica ATCC 39073, Candida boidinii, Candida methylica, and Saccharomyces cerevisiae S288c.

Protein GenBank ID GI Number Organism Moth_2312 YP_431142 148283121 Moorella thermoacetica Moth_2314 YP_431144 83591135 Moorella thermoacetica Sfum_2703 YP_846816.1 116750129 Syntrophobacter fumaroxidans Sfum_2704 YP_846817.1 116750130 Syntrophobacter fumaroxidans Sfum_2705 YP_846818.1 116750131 Syntrophobacter fumaroxidans Sfum_2706 YP_846819.1 116750132 Syntrophobacter fumaroxidans CHY_0731 YP_359585.1 78044572 Carboxydothermus hydrogenoformans CHY_0732 YP_359586.1 78044500 Carboxydothermus hydrogenoformans CHY_0733 YP_359587.1 78044647 Carboxydothermus hydrogenoformans CcarbDRAFT_(—) ZP_05390901.1 255523938 Clostridium 0901 carboxidivorans P7 CcarbDRAFT_(—) ZP_05394380.1 255527512 Clostridium 4380 carboxidivorans P7 fdhA, EIJ82879.1 387590560 Bacillus MGA3_06625 methanolicus MGA3 fdhA, ZP_10131761.1 387929084 Bacillus PB1_11719 methanolicus PB1 fdhD, EIJ82880.1 387590561 Bacillus MGA3_06630 methanolicus GA3 fdhD, ZP_10131762.1 387929085 Bacillus PB1_11724 methanolicus PB1 fdh ACF35003. 194220249 Burkholderia stabilis FDH1 AAC49766.1 2276465 Candida boidinii fdh CAA57036.1 1181204 Candida methylica FDH2 P0CF35.1 294956522 Saccharomyces cerevisiae S288c FDH1 NP_015033.1 6324964 Saccharomyces cerevisiae S288c

Alternately, a formate hydrogen lyase enzyme can be employed to convert formate to carbon dioxide and hydrogen. An exemplary formate hydrogen lyase enzyme can be found in Escherichia coli. The E. coli formate hydrogen lyase consists of hydrogenase 3 and formate dehydrogenase-H (Maeda et al., Appl Microbiol Biotechnol 77:879-890 (2007)). It is activated by the gene product of fhlA. (Maeda et al., Appl Microbiol Biotechnol 77:879-890 (2007)). The addition of the trace elements, selenium, nickel and molybdenum, to a fermentation broth has been shown to enhance formate hydrogen lyase activity (Soini et al., Microb. Cell Fact. 7:26 (2008)). Various hydrogenase 3, formate dehydrogenase and transcriptional activator genes are shown below. A formate hydrogen lyase enzyme also exists in the hyperthermophilic archaeon, Thermococcus litoralis (Takacs et al., BMC. Microbiol 8:88 (2008)). Additional formate hydrogen lyase systems have been found in Salmonella typhimurium, Klebsiella pneumoniae, Rhodospirillum rubrum, Methanobacterium formicicum (Vardar-Schara et al., Microbial Biotechnology 1:107-125 (2008)).

Protein GenBank ID GI number Organism hycA NP_417205 16130632 Escherichia coli K-12 MG1655 hycB NP_417204 16130631 Escherichia coli K-12 MG1655 hycC NP_417203 16130630 Escherichia coli K-12 MG1655 hycD NP_417202 16130629 Escherichia coli K-12 MG1655 hycE NP_417201 16130628 Escherichia coli K-12 MG1655 hycF NP_417200 16130627 Escherichia coli K-12 MG1655 hycG NP_417199 16130626 Escherichia coli K-12 MG1655 hycH NP_417198 16130625 Escherichia coli K-12 MG1655 hycI NP_417197 16130624 Escherichia coli K-12 MG1655 fdhF NP_418503 16131905 Escherichia coli K-12 MG1655 fhlA NP_417211 16130638 Escherichia coli K-12 MG1655 mhyC ABW05543 157954626 Thermococcus litoralis mhyD ABW05544 157954627 Thermococcus litoralis mhyE ABW05545 157954628 Thermococcus litoralis myhF ABW05546 157954629 Thermococcus litoralis myhG ABW05547 157954630 Thermococcus litoralis myhH ABW05548 157954631 Thermococcus litoralis fdhA AAB94932 2746736 Thermococcus litoralis fdhB AAB94931 157954625 Thermococcus litoralis

Pyruvate:NADP oxidoreductase (PNO) catalyzes the conversion of pyruvate to acetyl-CoA. This enzyme is encoded by a single gene and the active enzyme is a homodimer, in contrast to the multi-subunit PDH enzyme complexes described above. The enzyme from Euglena gracilis is stabilized by its cofactor, thiamin pyrophosphate (Nakazawa et al, Arch Biochem Biophys 411:183-8 (2003)). The mitochondrial targeting sequence of this enzyme should be removed for expression in the cytosol. The PNO protein of E. gracilis protein and other NADP-dependant pyruvate:NADP+ oxidoreductase enzymes are listed in the table below.

Protein GenBank ID GI Number Organism PNO Q94IN5.1 33112418 Euglena gracilis cgd4_690 XP_625673.1 66356990 Crypto- sporidium parvum Iowa II TPP_PFOR_PNO XP_002765111.11 294867463 Perkinsus marinus ATCC 50983

The NAD(P)⁺ dependent oxidation of acetaldehyde to acetyl-CoA (FIG. 2I) can be catalyzed by an acylating acetaldehyde dehydrogenase (EC 1.2.1.10). Acylating acetaldehyde dehydrogenase enzymes of E. coli are encoded by adhE, cutE, and mhpF (Ferrandez et al, J Bacteriol 179:2573-81 (1997)). The Pseudomonas sp. CF600 enzyme, encoded by dmpF, participates in meta-cleavage pathways and forms a complex with 4-hydroxy-2-oxovalerate aldolase (Shingler et al, J Bacteriol 174:711-24 (1992)). Solventogenic organisms such as Clostridium acetobutylicum encode bifunctional enzymes with alcohol dehydrogenase and acetaldehyde dehydrogenase activities. The bifunctional C. acetobutylicum enzymes are encoded by bdh I and adhE2 (Walter, et al., J. Bacteriol. 174:7149-7158 (1992); Fontaine et al., J. Bacteriol. 184:821-830 (2002)). Yet another candidate for acylating acetaldehyde dehydrogenase is the ald gene from Clostridium beijerinckii (Toth, Appl. Environ. Microbiol. 65:4973-4980 (1999). This gene is very similar to the cutE acetaldehyde dehydrogenase genes of Salmonella typhimurium and E. coli (Toth, Appl. Environ. Microbiol. 65:4973-4980 (1999).

Protein GenBank ID GI Number Organism adhE NP_415757.1 16129202 Escherichia coli mhpF NP_414885.1 16128336 Escherichia coli dmpF CAA43226.1 45683 Pseudomonas sp. CF600 adhE2 AAK09379.1 12958626 Clostridium acetobutylicum bdh I NP_349892.1 15896543 Clostridium acetobutylicum Ald AAT66436 49473535 Clostridium beijerinckii eutE NP_416950 16130380 Escherichia coli eutE AAA80209 687645 Salmonella typhimurium

Threonine aldolase (EC 4.1.2.5) catalyzes the cleavage of threonine to glycine and acetaldehyde (FIG. 2J). The Saccharomyces cerevisiae and Candida albicans enzymes are encoded by GLY1 (Liu et al, Eur J Biochem 245:289-93 (1997); McNeil et al, Yeast 16:167-75 (2000)). The ltaE and glyA gene products of E. coli also encode enzymes with this activity (Liu et al, Eur J Biochem 255:220-6 (1998)).

Protein GenBank ID GI Number Organism GLY1 NP_010868.1 6320789 Saccharomyces cerevisiae GLY1 AAB64198.1 2282060 Candida albicans ltaE AAC73957.1 1787095 Escherichia coli glyA AAC75604.1 1788902 Escherichia coli

Example III Pathways for Producing Acetyl-CoA from PEP and Pyruvate

Pathways for the conversion of cytosolic phosphoenolpyruvate (PEP) and pyruvate to cytosolic acetyl-CoA can also enable deployment of a cytosolic fatty alcohol, fatty aldehyde or fatty acid production pathway from acetyl-CoA. FIG. 3 shows numerous pathways for converting PEP and pyruvate to acetyl-CoA.

The conversion of PEP to oxaloacetate is catalyzed in one, two or three enzymatic steps. Oxaloacetate is further converted to acetyl-CoA via malonate semialdehyde or malonyl-CoA intermediates. In one pathway, PEP carboxylase or PEP carboxykinase converts PEP to oxaloacetate (step A); oxaloacetate decarboxylase converts the oxaloacetate to malonate (step B); and malonate semialdehyde dehydrogenase (acetylating) converts the malonate semialdehyde to acetyl-CoA (step C). In another pathway pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); pyruvate carboxylase converts the pyruvate to (step H); oxaloacetate decarboxylase converts the oxaloacetate to malonate (step B); and malonate semialdehyde dehydrogenase (acetylating) converts the malonate semialdehyde to acetyl-CoA (step C). In another pathway pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); malic enzyme converts the pyruvate to malate (step L); malate dehydrogenase or oxidoreductase converts the malate to oxaloacetate (step M); oxaloacetate decarboxylase converts the oxaloacetate to malonate (step B); and malonate semialdehyde dehydrogenase (acetylating) converts the malonate semialdehyde to acetyl-CoA (step C). In another pathway, PEP carboxylase or PEP carboxykinase converts PEP to oxaloacetate (step A); oxaloacetate decarboxylase converts the oxaloacetate to malonate semialdehyde (step B); malonyl-CoA reductase converts the malonate semialdehyde to malonyl-CoA (step G); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step (D). In another pathway, pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); pyruvate carboxylase converts the pyruvate to oxaloacetate (step H); (oxaloacetate decarboxylase converts the oxaloacetate to malonate semialdehyde (step B); malonyl-CoA reductase converts the malonate semialdehyde to malonyl-CoA (step G); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step (D). In another pathway, pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); malic enzyme converts the pyruvate to malate (step L); malate dehydrogenase or oxidoreductase converts the malate to oxaloacetate (step M); oxaloacetate decarboxylase converts the oxaloacetate to malonate semialdehyde (step B); malonyl-CoA reductase converts the malonate semialdehyde to malonyl-CoA (step G); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step (D). In another pathway, PEP carboxylase or PEP carboxykinase converts PEP to oxaloacetate (step A); oxaloacetate decarboxylase converts the oxaloacetate to malonate semialdehyde (step B); malonate semialdehyde dehydrogenase converts the malonate semialdehyde to malonate (step J); malonyl-CoA synthetase or transferase converts the malonate to malonyl-CoA (step K); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step D). In another pathway, pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); pyruvate carboxylase converts the pyruvate to oxaloacetate (step H); oxaloacetate decarboxylase converts the oxaloacetate to malonate semialdehyde (step B); malonate semialdehyde dehydrogenase converts the malonate semialdehyde to malonate (step J); malonyl-CoA synthetase or transferase converts the malonate to malonyl-CoA (step K); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step D). In another pathway, pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); malic enzyme converts the pyruvate to malate (step L); malate dehydrogenase or oxidoreductase converts the malate to oxaloacetate (step M); oxaloacetate decarboxylase converts the oxaloacetate to malonate semialdehyde (step B); malonate semialdehyde dehydrogenase converts the malonate semialdehyde to malonate (step J); malonyl-CoA synthetase or transferase converts the malonate to malonyl-CoA (step K); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step D). In another pathway, PEP carboxylase or PEP carboxykinase converts PEP to oxaloacetate (step A); oxaloacetate dehydrogenase or oxaloacetate oxidoreductase converts the oxaloacetate to malonyl-CoA (step F); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step D). In another pathway, pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); pyruvate carboxylase converts the pyruvate to oxaloacetate (step H); oxaloacetate dehydrogenase or oxaloacetate oxidoreductase converts the oxaloacetate to malonyl-CoA (step F); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step D). In another pathway, pyruvate kinase or PEP phosphatase converts PEP to pyruvate (step N); malic enzyme converts the pyruvate to malate (step L); malate dehydrogenase or oxidoreductase converts the malate to oxaloacetate (step M); oxaloacetate dehydrogenase or oxaloacetate oxidoreductase converts the oxaloacetate to malonyl-CoA (step F); and malonyl-CoA decarboxylase converts the malonyl-CoA to acetyl-CoA (step D).

Enzymes candidates for the reactions shown in FIG. 3 are described below.

1.1.n.a Oxidoreductase (alcohol to oxo) M 1.1.1.d Malic enzyme L 1.2.1.a Oxidoreductase (aldehyde to acid) J 1.2.1.b Oxidoreductase (acyl-CoA to aldehyde) G 1.2.1.f Oxidoreductase (decarboxylating acyl-CoA to C aldehyde) 2.7.2.a Kinase N 2.8.3.a CoA transferase K 3.1.3.a Phosphatase N 4.1.1.a Decarboxylase A, B, D 6.2.1.a CoA synthetase K 6.4.1.a Carboxylase D, H

Enzyme candidates for several enzymes in FIG. 3 have been described elsewhere herein. These include acetyl-CoA carboxylase, acetoacetyl-CoA synthase, acetoacetyl-CoA thiolase, malonyl-CoA reductase (also called malonate semialdehyde dehydrogenase (acylating), malate dehydrogenase.

1.1.n.a Oxidoreductase (Alcohol to Oxo)

Malate dehydrogenase or oxidoreductase catalyzes the oxidation of malate to oxaloacetate. Different carriers can act as electron acceptors for enzymes in this class. Malate dehydrogenase enzymes utilize NADP or NAD as electron acceptors. Malate dehydrogenase (Step M) enzyme candidates are described above in example 1 (Table 7, 23). Malate:quinone oxidoreductase enzymes (EC 1.1.5.4) are membrane-associated and utilize quinones, flavoproteins or vitamin K as electron acceptors. Malate:quinone oxidoreductase enzymes of E. coli, Helicobacter pylori and Pseudomonas syringae are encoded by mqo (Kather et al, J Bacteriol 182:3204-9 (2000); Mellgren et al, J Bacteriol 191:3132-42 (2009)). The Cgl2001 gene of C. gluamicum also encodes an MQO enzyme (Mitsuhashi et al, Biosci Biotechnol Biochem 70:2803-6 (2006)).

Protein GenBank ID GI Number Organism mqo NP_416714.1 16130147 Escherichia coli mqo NP_206886.1 15644716 Helicobacter pylori mqo NP_790970.1 28868351 Pseudomonas syringae Cgl2001 NP_601207.1 19553205 Corynebacterium glutamicum

1.1.1.d Malic Enzyme

Malic enzyme (malate dehydrogenase) catalyzes the reversible oxidative carboxylation of pyruvate to malate. E. coli encodes two malic enzymes, MaeA and MaeB (Takeo, J. Biochem. 66:379-387 (1969)). Although malic enzyme is typically assumed to operate in the direction of pyruvate formation from malate, the NAD-dependent enzyme, encoded by maeA, has been demonstrated to operate in the carbon-fixing direction (Stols and Donnelly, Appl. Environ. Microbiol. 63(7) 2695-2701 (1997)). A similar observation was made upon overexpressing the malic enzyme from Ascaris suum in E. coli (Stols et al., Appl. Biochem. Biotechnol. 63-65(1), 153-158 (1997)). The second E. coli malic enzyme, encoded by maeB, is NADP-dependent and also decarboxylates oxaloacetate and other alpha-keto acids (Iwakura et al., J. Biochem. 85(5):1355-65 (1979)). Another suitable enzyme candidate is mel from Zea mays (Furumoto et al, Plant Cell Physiol 41:1200-1209 (2000)).

Protein GenBank ID GI Number Organism maeA NP_415996 90111281 Escherichia coli maeB NP_416958 16130388 Escherichia coli NAD-ME P27443 126732 Ascaris suum Mel P16243.1 126737 Zea mays

1.2.1.a Oxidoreductase (Aldehyde to Acid)

The oxidation of malonate semialdehyde to malonate is catalyzed by malonate semialdehyde dehydrogenase (EC 1.2.1.15). This enzyme was characterized in Pseudomonas aeruginosa (Nakamura et al, Biochim Biophys Acta 50:147-52 (1961)). The NADP and NAD-dependent succinate semialdehyde dehydrogenase enzymes of Euglena gracilas accept malonate semialdehyde as substrates (Tokunaga et al, Biochem Biophys Act 429:55-62 (1976)). Genes encoding these enzymes has not been identified to date. Aldehyde dehydrogenase enzymes from eukoryotic organisms such as S. cerevisiae, C. albicans, Y. lipolytica and A. niger typically have broad substrate specificity and are suitable candidates. These enzymes and other acid forming aldehyde dehydrogenase and aldehyde oxidase enzymes are described earlier and listed in Tables 9 and 30. Additional MSA dehydrogenase enzyme candidates include NAD(P)+-dependent aldehyde dehydrogenase enzymes (EC 1.2.1.3). Two aldehyde dehydrogenases found in human liver, ALDH-1 and ALDH-2, have broad substrate ranges for a variety of aliphatic, aromatic and polycyclic aldehydes (Klyosov, Biochemistry 35:4457-4467 (1996a)). Active ALDH-2 has been efficiently expressed in E. coli using the GroEL proteins as chaperonins (Lee et al., Biochem. Biophys. Res. Commun. 298:216-224 (2002)). The rat mitochondrial aldehyde dehydrogenase also has a broad substrate range (Siew et al., Arch. Biochem. Biophys. 176:638-649 (1976)). The E. coli genes astD and aldH encode NAD+-dependent aldehyde dehydrogenases. AstD is active on succinic semialdehyde (Kuznetsova et al., FEMS Microbiol Rev 29:263-279 (2005)) and aldH is active on a broad range of aromatic and aliphatic substrates (Jo et al, Appl Microbiol Biotechnol 81:51-60 (2008)).

Gene GenBank Accession No. GI No. Organism astD P76217.1 3913108 Escherichia coli aldH AAC74382.1 1787558 Escherichia coli ALDH-2 P05091.2 118504 Homo sapiens ALDH-2 NP_115792.1 14192933 Rattus norvegicus

1.2.1.f Oxidoreductase (Decarboxylating Acyl-CoA to Aldehyde)

Malonate semialdehyde dehydrogenase (acetylating) (EC 1.2.1.18) catalyzes the oxidative decarboxylation of malonate semialdehyde to acetyl-CoA. Exemplary enzymes are encoded by ddcC of Halomonas sp. HTNKJ (Todd et al, Environ Microbiol 12:237-43 (2010)) and IolA of Lactobacillus casei (Yebra et al, AEM 73:3850-8 (2007)). The DdcC enzyme has homologs in A. niger and C. albicans, shown in the table below. The malonate semialdehyde dehydrogenase enzyme in Rattus norvegicus, Mmsdh, also converts malonate semialdehyde to acetyl-CoA (U.S. Pat. No. 8,048,624). A malonate semialdehyde dehydrogenase (acetylating) enzyme has also been characterized in Pseudomonas fluorescens, although the gene has not been identified to date (Hayaishi et al, J Biol Chem 236:781-90 (1961)). Methylmalonate semialdehyde dehydrogenase (acetylating) enzymes (EC 1.2.1.27) are also suitable candidates, as several enzymes in this class accept malonate semialdehyde as a substrate including Msdh of Bacillus subtilis (Stines-Chaumeil et al, Biochem J 395:107-15 (2006)) and the methylmalonate semialdehyde dehydrogenase of R. norvegicus (Kedishvii et al, Methods Enzymol 324:207-18 (2000)).

Protein GenBank ID GI Number Organism ddcC ACV84070.1 258618587 Halomonas sp. HTNK1 ANI_1_1120014 XP_001389265.1 145229913 Aspergillus niger ALD6 XP_710976.1 68490403 Candida albicans YALI0C01859g XP_501343.1 50547747 Yarrowia lipolytica mmsA_1 YP_257876.1 70734236 Pseudomonas fluorescens mmsA_2 YP_257884.1 70734244 Pseudomonas fluorescens PA0130 NP_248820.1 15595328 Pseudomonas aeruginosa Mmsdh Q02253.1 400269 Rattus norvegicus msdh NP_391855.1 16081027 Bacillus subtilis IolA ABP57762.1 145309085 Lactobacillus casei

2.7.2.a Kinase

Pyruvate kinase (Step 10N), also known as phosphoenolpyruvate synthase (EC 2.7.9.2), converts pyruvate and ATP to PEP and AMP. This enzyme is encoded by the PYK1 (Burke et al., J. Biol. Chem. 258:2193-2201 (1983)) and PYK2 (Boles et al., J. Bacteriol. 179:2987-2993 (1997)) genes in S. cerevisiae. In E. coli, this activity is catalyzed by the gene products of pykF and pykA. Selected homologs of the S. cerevisiae enzymes are also shown in the table below.

Protein GenBank ID GI Number Organism PYK1 NP_009362 6319279 Saccharomyces cerevisiae PYK2 NP_014992 6324923 Saccharomyces cerevisiae pykF NP_416191.1 16129632 Escherichia coli pykA NP_416368.1 16129807 Escherichia coli KLLA0F23397g XP_456122.1 50312181 Kluyveromyces lactis CaO19.3575 XP_714934.1 68482353 Candida albicans CaO19.11059 XP_714997.1 68482226 Candida albicans YALI0F09185p XP_505195 210075987 Yarrowia lipolytica ANI_1_1126064 XP_001391973 145238652 Aspergillus niger

2.8.3.a CoA Transferase

Activation of malonate to malonyl-CoA is catalyzed by a CoA transferase in EC class 2.8.3.a. Malonyl-CoA:acetate CoA transferase (EC 2.8.3.3) enzymes have been characterized in Pseudomonas species including Pseudomonas fluorescens and Pseudomonas putida (Takamura et al, Biochem Int 3:483-91 (1981); Hayaishi et al, J Biol Chem 215:125-36 (1955)). Genes associated with these enzymes have not been identified to date. A mitochondrial CoA transferase found in Rattus norvegicus liver also catalyzes this reaction and is able to utilize a range of CoA donors and acceptors (Deana et al, Biochem Int 26:767-73 (1992)). Several CoA transferase enzymes described above can also be applied to catalyze step K of FIG. 10. These enzymes include acetyl-CoA transferase (Table 26), 3-HB CoA transferase (Table 8), acetoacetyl-CoA transferase (table 55), SCOT (table 56) and other CoA transferases (table 57).

3.1.3.a Phosphatase

Phosphoenolpyruvate phosphatase (EC 3.1.3.60, Step 10N) catalyzes the hydrolysis of PEP to pyruvate and phosphate. Numerous phosphatase enzymes catalyze this activity, including alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), phosphoglycerate phosphatase (EC 3.1.3.20) and PEP phosphatase (EC 3.1.3.60). PEP phosphatase enzymes have been characterized in plants such as Vignia radiate, Bruguiera sexangula and Brassica nigra. The phytase from Aspergillus fumigates, the acid phosphatase from Homo sapiens and the alkaline phosphatase of E. coli also catalyze the hydrolysis of PEP to pyruvate (Brugger et al, Appl Microbiol Biotech 63:383-9 (2004); Hayman et al, Biochem J 261:601-9 (1989); et al, The Enzymes 3^(rd) Ed. 4:373-415 (1971))). Similar enzymes have been characterized in Campylobacter jejuni (van Mourik et al., Microbiol. 154:584-92 (2008)), Saccharomyces cerevisiae (Oshima et al., Gene 179:171-7 (1996)) and Staphylococcus aureus (Shah and Blobel, J. Bacteriol. 94:780-1 (1967)). Enzyme engineering and/or removal of targeting sequences may be required for alkaline phosphatase enzymes to function in the cytoplasm.

Protein GenBank ID GI Number Organism phyA O00092.1 41017447 Aspergillus fumigatus Acp5 P13686.3 56757583 Homo sapiens phoA NP_414917.2 49176017 Escherichia coli phoX ZP_01072054.1 86153851 Campylobacter jejuni PHO8 AAA34871.1 172164 Saccharomyces cerevisiae SaurJH1_2706 YP_001317815.1 150395140 Staphylococcus aureus

4.1.1.a Decarboxylase

Several reactions in FIG. 10 are catalyzed by decarboxylase enzymes in EC class 4.1.1, including oxaloacetate decarboxylase (Step B), malonyl-CoA decarboxylase (step D) and pyruvate carboxylase or carboxykinase (step A).

Carboxylation of phosphoenolpyruvate to oxaloacetate is catalyzed by phosphoenolpyruvate carboxylase (EC 4.1.1.31). Exemplary PEP carboxylase enzymes are encoded by ppc in E. coli (Kai et al., Arch. Biochem. Biophys. 414:170-179 (2003), ppcA in Methylobacterium extorquens AM1 (Arps et al., J. Bacteriol. 175:3776-3783 (1993), and ppc in Corynebacterium glutamicum (Eikmanns et al., Mol. Gen. Genet. 218:330-339 (1989).

Protein GenBank ID GI Number Organism Ppc NP_418391 16131794 Escherichia coli ppcA AAB58883 28572162 Methylobacterium extorquens Ppc ABB53270 80973080 Corynebacterium glutamicum

An alternative enzyme for carboxylating phosphoenolpyruvate to oxaloacetate is PEP carboxykinase (EC 4.1.1.32, 4.1.1.49), which simultaneously forms an ATP or GTP. In most organisms PEP carboxykinase serves a gluconeogenic function and converts oxaloacetate to PEP at the expense of one ATP. S. cerevisiae is one such organism whose native PEP carboxykinase, PCK1, serves a gluconeogenic role (Valdes-Hevia et al., FEBS Lett. 258:313-316 (1989). E. coli is another such organism, as the role of PEP carboxykinase in producing oxaloacetate is believed to be minor when compared to PEP carboxylase (Kim et al., Appl. Environ. Microbiol. 70:1238-1241 (2004)). Nevertheless, activity of the native E. coli PEP carboxykinase from PEP towards oxaloacetate has been recently demonstrated in ppc mutants of E. coli K-12 (Kwon et al., J. Microbiol. Biotechnol. 16:1448-1452 (2006)). These strains exhibited no growth defects and had increased succinate production at high NaHCO₃ concentrations. Mutant strains of E. coli can adopt Pck as the dominant CO₂-fixing enzyme following adaptive evolution (Zhang et al. 2009). In some organisms, particularly rumen bacteria, PEP carboxykinase is quite efficient in producing oxaloacetate from PEP and generating ATP. Examples of PEP carboxykinase genes that have been cloned into E. coli include those from Mannheimia succiniciproducens (Lee et al., Biotechnol. Bioprocess Eng. 7:95-99 (2002)), Anaerobiospirillum succiniciproducens (Laivenieks et al., Appl. Environ. Microbiol. 63:2273-2280 (1997), and Actinobacillus succinogenes (Kim et al. supra). The PEP carboxykinase enzyme encoded by Haemophilus influenza is effective at forming oxaloacetate from PEP. Another suitable candidate is the PEPCK enzyme from Megathyrsus maximus, which has a low Km for CO₂, a substrate thought to be rate-limiting in the E. coli enzyme (Chen et al., Plant Physiol 128:160-164 (2002); Cotelesage et al., Int. J Biochem. Cell Biol. 39:1204-1210 (2007)). The kinetics of the GTP-dependent pepck gene product from Cupriavidus necator favor oxaloacetate formation (U.S. Pat. No. 8,048,624 and Lea et al, Amino Acids 20:225-41 (2001)).

Protein GenBank ID GI Number Organism PCK1 NP_013023 6322950 Saccharomyces cerevisiae pck NP_417862.1 16131280 Escherichia coli pckA NP_089485.1 52426348 Mannheimia succiniciproducens pckA O09460.1 3122621 Anaerobiospirillum succiniciproducens pckA Q6W6X5 75440571 Actinobacillus succinogenes pckA P43923.1 1172573 Haemophilus influenza AF532733.1:1 . . . 1929 AAQ10076.1 33329363 Megathyrsus maximus pepck YP_728135.1 113869646 Cupriavidus necator

Oxaloacetate decarboxylase catalyzes the decarboxylation of oxaloacetate to malonate semialdehyde. Enzymes catalyzing this reaction include kgd of Mycobacterium tuberculosis (GenBank ID: O50463.4, GI: 160395583). Enzymes evolved from kgd with improved activity and/or substrate specificity for oxaloacetate have also been described (U.S. Pat. No. 8,048,624). Additional enzymes useful for catalyzing this reaction include keto-acid decarboxylases shown in the table below.

EC number Name 4.1.1.1 Pyruvate decarboxylase 4.1.1.7 Benzoylformate decarboxylase 4.1.1.40 Hydroxypyruvate decarboxylase 4.1.1.43 Ketophenylpyruvate decarboxylase 4.1.1.71 Alpha-ketoglutarate decarboxylase 4.1.1.72 Branched chain keto-acid decarboxylase 4.1.1.74 Indolepyruvate decarboxylase 4.1.1.75 2-Ketoarginine decarboxylase 4.1.1.79 Sulfopyruvate decarboxylase 4.1.1.80 Hydroxyphenylpyruvate decarboxylase 4.1.1.82 Phosphonopyruvate decarboxylase

The decarboxylation of keto-acids is catalyzed by a variety of enzymes with varied substrate specificities, including pyruvate decarboxylase (EC 4.1.1.1), benzoylformate decarboxylase (EC 4.1.1.7), alpha-ketoglutarate decarboxylase and branched-chain alpha-ketoacid decarboxylase. Pyruvate decarboxylase (PDC), also termed keto-acid decarboxylase, is a key enzyme in alcoholic fermentation, catalyzing the decarboxylation of pyruvate to acetaldehyde. The PDC 1 enzyme from Saccharomyces cerevisiae has a broad substrate range for aliphatic 2-keto acids including 2-ketobutyrate, 2-ketovalerate, 3-hydroxypyruvate and 2-phenylpyruvate (22). This enzyme has been extensively studied, engineered for altered activity, and functionally expressed in E. coli (Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001); Li et al., Biochemistry. 38:10004-10012 (1999); ter Schure et al., Appl. Environ. Microbiol. 64:1303-1307 (1998)). The PDC from Zymomonas mobilus, encoded by pdc, also has a broad substrate range and has been a subject of directed engineering studies to alter the affinity for different substrates (Siegert et al., Protein Eng Des Sel 18:345-357 (2005)). The crystal structure of this enzyme is available (Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001)). Other well-characterized PDC candidates include the enzymes from Acetobacter pasteurians (Chandra et al., 176:443-451 (2001)) and Kluyveromyces lactis (Krieger et al., 269:3256-3263 (2002)).

Protein GenBank ID GI Number Organism pdc P06672.1 118391 Zymomonas mobilis pdc1 P06169 30923172 Saccharomyces cerevisiae pdc Q8L388 20385191 Acetobacter pasteurians pdc1 Q12629 52788279 Kluyveromyces lactis

Like PDC, benzoylformate decarboxylase (EC 4.1.1.7) has a broad substrate range and has been the target of enzyme engineering studies. The enzyme from Pseudomonas putida has been extensively studied and crystal structures of this enzyme are available (Polovnikova et al., 42:1820-1830 (2003); Hasson et al., 37:9918-9930 (1998)). Site-directed mutagenesis of two residues in the active site of the Pseudomonas putida enzyme altered the affinity (Km) of naturally and non-naturally occurring substrates (Siegert et al., Protein Eng Des Sel 18:345-357 (2005)). The properties of this enzyme have been further modified by directed engineering (Lingen et al., Chembiochem. 4:721-726 (2003); Lingen et al., Protein Eng 15:585-593 (2002)). The enzyme from Pseudomonas aeruginosa, encoded by mdlC, has also been characterized experimentally (Barrowman et al., 34:57-60 (1986)). Additional gene candidates from Pseudomonas stutzeri, Pseudomonas fluorescens and other organisms can be inferred by sequence homology or identified using a growth selection system developed in Pseudomonas putida (Henning et al., Appl. Environ. Microbiol. 72:7510-7517 (2006)).

Protein GenBank ID GI Number Organism mdlC P20906.2 3915757 Pseudomonas putida mdlC Q9HUR2.1 81539678 Pseudomonas aeruginosa dpgB ABN80423.1 126202187 Pseudomonas stutzeri ilvB-1 YP_260581.1 70730840 Pseudomonas fluorescens

A third enzyme capable of decarboxylating 2-oxoacids is alpha-ketoglutarate decarboxylase (KGD, EC 4.1.1.71). The substrate range of this class of enzymes has not been studied to date. An exemplary KDC is encoded by kad in Mycobacterium tuberculosis (Tian et al., PNAS 102:10670-10675 (2005)). KDC enzyme activity has also been detected in several species of rhizobia including Bradyrhizobium japonicum and Mesorhizobium loti (Green et al., J Bacteriol 182:2838-2844 (2000)). Although the KDC-encoding gene(s) have not been isolated in these organisms, the genome sequences are available and several genes in each genome are annotated as putative KDCs. A KDC from Euglena gracilis has also been characterized but the gene associated with this activity has not been identified to date (Shigeoka et al., Arch. Biochem. Biophys. 288:22-28 (1991)). The first twenty amino acids starting from the N-terminus were sequenced MTYKAPVKDVKFLLDKVFKV (SEQ ID NO: 8) (Shigeoka and Nakano, Arch. Biochem. Biophys. 288:22-28 (1991)). The gene could be identified by testing candidate genes containing this N-terminal sequence for KDC activity. A novel class of AKG decarboxylase enzymes has recently been identified in cyanobacteria such as Synechococcus sp. PCC 7002 and homologs (Zhang and Bryant, Science 334:1551-3 (2011)).

Protein GenBank ID GI Number Organism kgd O50463.4 160395583 Mycobacterium tuberculosis kgd NP_767092.1 27375563 Bradyrhizobium japonicum USDA110 kgd NP_105204.1 13473636 Mesorhizobium loti ilvB ACB00744.1 169887030 Synechococcus sp. PCC 7002

A fourth candidate enzyme for catalyzing this reaction is branched chain alpha-ketoacid decarboxylase (BCKA). This class of enzyme has been shown to act on a variety of compounds varying in chain length from 3 to 6 carbons (Oku et al., J Biol Chem. 263:18386-18396 (1988); Smit et al., Appl Environ Microbiol 71:303-311 (2005)). The enzyme in Lactococcus lactis has been characterized on a variety of branched and linear substrates including 2-oxobutanoate, 2-oxohexanoate, 2-oxopentanoate, 3-methyl-2-oxobutanoate, 4-methyl-2-oxobutanoate and isocaproate (Smit et al., Appl Environ Microbiol 71:303-311 (2005)). The enzyme has been structurally characterized (Berg et al., Science. 318:1782-1786 (2007)). Sequence alignments between the Lactococcus lactis enzyme and the pyruvate decarboxylase of Zymomonas mobilus indicate that the catalytic and substrate recognition residues are nearly identical (Siegert et al., Protein Eng Des Sel 18:345-357 (2005)), so this enzyme would be a promising candidate for directed engineering. Several ketoacid decarboxylases of Saccharomyces cerevisiae catalyze the decarboxylation of branched substrates, including ARO10, PDC6, PDC5, PDC1 and THI3 (Dickenson et al, J Biol Chem 275:10937-42 (2000)). Yet another BCKAD enzyme is encoded by rv0853c of Mycobacterium tuberculosis (Werther et al, J Biol Chem 283:5344-54 (2008)). This enzyme is subject to allosteric activation by alpha-ketoacid substrates. Decarboxylation of alpha-ketoglutarate by a BCKA was detected in Bacillus subtilis; however, this activity was low (5%) relative to activity on other branched-chain substrates (Oku and Kaneda, J Biol Chem. 263:18386-18396 (1988)) and the gene encoding this enzyme has not been identified to date. Additional BCKA gene candidates can be identified by homology to the Lactococcus lactis protein sequence. Many of the high-scoring BLASTp hits to this enzyme are annotated as indolepyruvate decarboxylases (EC 4.1.1.74). Indolepyruvate decarboxylase (IPDA) is an enzyme that catalyzes the decarboxylation of indolepyruvate to indoleacetaldehyde in plants and plant bacteria. Recombinant branched chain alpha-keto acid decarboxylase enzymes derived from the E1 subunits of the mitochondrial branched-chain keto acid dehydrogenase complex from Homo sapiens and Bos taurus have been cloned and functionally expressed in E. coli (Davie et al., J. Biol. Chem. 267:16601-16606 (1992); Wynn et al., J. Biol. Chem. 267:12400-12403 (1992); Wynn et al., J. Biol. Chem. 267:1881-1887 (1992)). In these studies, the authors found that co-expression of chaperonins GroEL and GroES enhanced the specific activity of the decarboxylase by 500-fold (Wynn et al., J. Biol. Chem. 267:12400-12403 (1992)). These enzymes are composed of two alpha and two beta subunits.

Protein GenBank ID GI Number Organism kdcA AAS49166.1 44921617 Lactococcus lactis PDC6 NP_010366.1 6320286 Saccharomyces cerevisiae PDC5 NP_013235.1 6323163 Saccharomyces cerevisiae PDC1 P06169 30923172 Saccharomyces cerevisiae ARO10 NP_010668.1 6320588 Saccharomyces cerevisiae THI3 NP_010203.1 6320123 Saccharomyces cerevisiae rv0853c O53865.1 81343167 Mycobacterium tuberculosis BCKDHB NP_898871.1 34101272 Homo sapiens BCKDHA NP_000700.1 11386135 Homo sapiens BCKDHB P21839 115502434 Bos taurus BCKDHA P11178 129030 Bos taurus

3-Phosphonopyruvate decarboxylase (EC 4.1.1.82) catalyzes the decarboxylation of 3-phosphonopyruvate to 2-phosphonoacetaldehyde. Exemplary phosphonopyruvate decarboxylase enzymes are encoded by dhpF of Streptomyces luridus, ppd of Streptomyces viridochromogenes, fom2 of Streptomyces wedmorensis and bcpC of Streptomyces hygroscopius (Circello et al, Chem Biol 17:402-11 (2010); Blodgett et al, FEMS Microbiol Lett 163:149-57 (2005); Hidaka et al, Mol Gen Genet 249:274-80 (1995); Nakashita et al, Biochim Biophys Acta 1490:159-62 (2000)). The Bacteroides fragilis enzyme, encoded by aepY, also decarboxylates pyruvate and sulfopyruvate (Zhang et al, J Biol Chem 278:41302-8 (2003)).

Protein GenBank ID GI Number Organism dhpF ACZ13457.1 268628095 Streptomyces luridus Ppd CAJ14045.1 68697716 Streptomyces viridochromogenes Fom2 BAA32496.1 1061008 Streptomyces wedmorensis aepY AAG26466.1 11023509 Bacteroides fragilis

Many oxaloacetate decarboxylase enzymes such as the eda gene product in E. coli (EC 4.1.1.3), act on the terminal acid of oxaloacetate to form pyruvate. Because decarboxylation at the 3-keto acid position competes with the malonate semialdehyde forming decarboxylation at the 2-keto-acid position, this enzyme activity can be knocked out in a host strain with a pathway proceeding through a malonate semialdehyde intermediate.

Malonyl-CoA decarboxylase (EC 4.1.1.9) catalyzes the decarboxylation of malonyl-CoA to acetyl-CoA. Enzymes have been characterized in Rhizobium leguminosarum and Acinetobacter calcoaceticus (An et al, Eur J Biochem 257: 395-402 (1998); Koo et al, Eur J Biochem 266:683-90 (1999)). Similar enzymes have been characterized in Streptomyces erythreus (Hunaiti et al, Arch Biochem Biophys 229:426-39 (1984)). A recombinant human malonyl-CoA decarboxylase was overexpressed in E. coli (Zhou et al, Prot Expr Pur 34:261-9 (2004)). Methylmalonyl-CoA decarboxylase enzymes that decarboxylate malonyl-CoA are also suitable candidates. For example, the Veillonella parvula enzyme accepts malonyl-CoA as a substrate (Hilpert et al, Nature 296:584-5 (1982)). The E. coli enzyme is encoded by ygfG (Benning et al., Biochemistry. 39:4630-4639 (2000); Haller et al., Biochemistry. 39:4622-4629 (2000)). The stereo specificity of the E. coli enzyme was not reported, but the enzyme in Propionigenium modestum (Bott et al., Eur. J. Biochem. 250:590-599 (1997)) and Veillonella parvula (Huder et al., J. Biol. Chem. 268:24564-24571 (1993)) catalyzes the decarboxylation of the (S)-stereoisomer of methylmalonyl-CoA (Hoffmann et al., FEBS. Lett. 220:121-125 (1987)). The enzymes from P. modestum and V. parvula are comprised of multiple subunits that not only decarboxylate (S)-methylmalonyl-CoA, but also create a pump that transports sodium ions across the cell membrane as a means to generate energy.

Protein GenBank ID GI Number Organism YgfG NP_417394 90111512 Escherichia coli matA Q9ZIP6 75424899 Rhizobium leguminosarum mdcD AAB97628.1 2804622 Acinetobacter calcoaceticus mdcE AAF20287.1 6642782 Acinetobacter calcoaceticus mdcA AAB97627.1 2804621 Acinetobacter calcoaceticus mdcC AAB97630.1 2804624 Acinetobacter calcoaceticus mcd NP_036345.2 110349750 Homo sapiens mmdA CAA05137 2706398 Propionigenium modestum mmdD CAA05138 2706399 Propionigenium modestum mmdC CAA05139 2706400 Propionigenium modestum mmdB CAA05140 2706401 Propionigenium modestum mmdA CAA80872 415915 Veillonella parvula mmdC CAA80873 415916 Veillonella parvula mmdE CAA80874 415917 Veillonella parvula mmdD CAA80875 415918 Veillonella parvula mmdB CAA80876 415919 Veillonella parvula

6.2.1.a CoA Synthetase

Activation of malonate to malonyl-CoA is catalyzed by a CoA synthetase in EC class 6.2.1.a. CoA synthetase enzymes that catalyze this reaction have not been described in the literature to date. Several CoA synthetase enzymes described above can also be applied to catalyze step K of FIG. 10. These enzymes include acetyl-CoA synthetase (Table 16, 25) and ADP forming CoA synthetases (Table 17).

6.4.1.a Carboxylase

Pyruvate carboxylase (EC 6.4.1.1) converts pyruvate to oxaloacetate at the cost of one ATP (step H). Exemplary pyruvate carboxylase enzymes are encoded by PYC1 (Walker et al., Biochem. Biophys. Res. Commun. 176:1210-1217 (1991) and PYC2 (Walker et al., supra) in Saccharomyces cerevisiae, and pyc in Mycobacterium smegmatis (Mukhopadhyay and Purwantini, Biochim. Biophys. Acta 1475:191-206 (2000)).

Protein GenBank ID GI Number Organism PYC1 NP_011453 6321376 Saccharomyces cerevisiae PYC2 NP_009777 6319695 Saccharomyces cerevisiae Pyc YP_890857.1 118470447 Mycobacterium smegmatis

Example IV Pathways for Producing Cytosolic Acetyl-CoA from Mitochondrial Acetyl-CoA

A mechanism for transporting acetyl-CoA from the mitochondrion to the cytosol can facilitate deployment of a cytosolic fatty alcohol, fatty aldehyde or fatty acid production pathway that originates from acetyl-CoA. Exemplary mechanisms for exporting acetyl-CoA include those depicted in FIGS. 4 and 5, which can involve forming citrate from acetyl-CoA and oxaloacetate in the mitochondrion, exporting the citrate from the mitochondrion to the cytosol, and converting the citrate to oxaloacetate and either acetate or acetyl-CoA. In certain embodiments, provided herein are methods for engineering a eukaryotic organism to increase its availability of cytosolic acetyl-CoA by introducing enzymes capable of carrying out the transformations depicted in any one of FIGS. 4 and 5. Exemplary enzymes capable of carrying out the required transformations are also disclosed herein.

The production of cytosolic acetyl-CoA from mitochondrial acetyl-CoA can be accomplished by a number of pathways, for example, in three to five enzymatic steps. In one exemplary pathway, mitochondrial acetyl-CoA and oxaloacetate are combined into citrate by a citrate synthase and the citrate is exported out of the mitochondrion by a citrate or citrate/oxaloacetate transporter. Enzymatic conversion of the citrate in the cytosol results in cytosolic acetyl-CoA and oxaloacetate. The cytosolic oxaloacetate can then optionally be transported back into the mitochondrion by an oxaloacetate transporter and/or a citrate/oxaloacetate transporter. In another exemplary pathway, the cytosolic oxaloacetate is first enzymatically converted into malate in the cytosol and then optionally transferred into the mitochondrion by a malate transporter and/or a malate/citrate transporter. Mitochondrial malate can then be converted into oxaloacetate with a mitochondrial malate dehydrogenase.

In yet another exemplary pathway, mitochondrial acetyl-CoA can be converted to cytosolic acetyl-CoA via a citramalate intermediate. For example, mitochondrial acetyl-CoA and pyruvate are converted to citramalate by citramalate synthase. Citramalate can then be transported into the cytosol by a citramalate or dicarboxylic acid transporter. Cytosolic acetyl-CoA and pyruvate are then regenerated from citramalate, directly or indirectly, and the pyruvate can re-enter the mitochondria.

Along these lines, several exemplary acetyl-CoA pathways for the production of cytosolic acetyl-CoA from mitochondrial acetyl-CoA are shown in FIGS. 4 and 5. In one embodiment, mitochondrial oxaloacetate is combined with mitochondrial acetyl-CoA to form citrate by a citrate synthase. The citrate is transported outside of the mitochondrion by a citrate transporter, a citrate/oxaloacetate transporter or a citrate/malate transporter. Cytosolic citrate is converted into cytosolic acetyl-CoA and oxaloacetate by an ATP citrate lyase. In another pathway, cytosolic citrate is converted into acetate and oxaloacetate by a citrate lyase. Acetate can then be converted into cytosolic acetyl-CoA by an acetyl-CoA synthetase or transferase. Alternatively, acetate can be converted by an acetate kinase to acetyl phosphate, and the acetyl phosphate can be converted to cytosolic acetyl-CoA by a phosphotransacetylase. Exemplary enzyme candidates for acetyl-CoA pathway enzymes are described below.

The conversion of oxaloacetate and mitochondrial acetyl-CoA is catalyzed by a citrate synthase (FIGS. 4 and 5, step A). In certain embodiments, the citrate synthase is expressed in a mitochondrion of a non-naturally occurring eukaryotic organism provided herein.

Protein GenBank ID GI number Organism CIT1 NP_014398.1 6324328 Saccharomyces cerevisiae S288c CIT2 NP_009931.1 6319850 Saccharomyces cerevisiae S288c CIT3 NP_015325.1 6325257 Saccharomyces cerevisiae S288c YALI0E02684p XP_503469.1 50551989 Yarrowia lipolytica YALI0E00638p XP_503380.1 50551811 Yarrowia lipolytica ANI_1_876084 XP_001393983.1 145242820 Aspergillus niger CBS 513.88 ANI_1_1474074 XP_001393195.2 317030721 Aspergillus niger CBS 513.88 ANI_1_2950014 XP_001389414.2 317026339 Aspergillus niger CBS 513.88 ANI_1_1226134 XP_001396731.1 145250435 Aspergillus niger CBS 513.88 gltA NP_415248.1 16128695 Escherichia coli K-12 MG1655

Transport of citrate from the mitochondrion to the cytosol can be carried out by several transport proteins. Such proteins either export citrate directly (i.e., citrate transporter, FIGS. 4 and 5, step B) to the cytosol or export citrate to the cytosol while simultaneously transporting a molecule such as malate (i.e., citrate/malate transporter, FIG. 4, step C) or oxaloacetate (i.e., citrate/oxaloacetate transporter FIG. 5, step C) from the cytosol into the mitochondrion as shown in FIGS. 4 and 5. Exemplary transport enzymes that carry out these transformations are provided in the table below.

Protein GenBank ID GI number Organism CTP1 NP_009850.1 6319768 Saccharomyces cerevisiae S288c YALI0F26323p XP_505902.1 50556988 Yarrowia lipolytica ATEG_09970 EAU29419.1 114187719 Aspergillus terreus NIH2624 KLLA0E18723g XP_454797.1 50309571 Kluyveromyces lactis NRRL Y-1140 CTRG_02320 XP_002548023.1 255726194 Candida tropicalis MYA-3404 ANI_1_1474094 XP_001395080.1 145245625 Aspergillus niger CBS 513.88 YHM2 NP_013968.1 6323897 Saccharomyces cerevisiae S288c DTC CAC84549.1 19913113 Arabidopsis thaliana DTC1 CAC84545.1 19913105 Nicotiana tabacum DTC2 CAC84546.1 19913107 Nicotiana tabacum DTC3 CAC84547.1 19913109 Nicotiana tabacum DTC4 CAC84548.1 19913111 Nicotiana tabacum DTC AAR06239.1 37964368 Citrus junos

ATP citrate lyase (ACL, EC 2.3.3.8, FIGS. 4 and 5, step D), also called ATP citrate synthase, catalyzes the ATP-dependent cleavage of citrate to oxaloacetate and acetyl-CoA. In certain embodiments, ATP citrate lyase is expressed in the cytosol of a eukaryotic organism. ACL is an enzyme of the RTCA cycle that has been studied in green sulfur bacteria Chlorobium limicola and Chlorobium tepidum. The alpha(4)beta(4) heteromeric enzyme from Chlorobium limicola was cloned and characterized in E. coli (Kanao et al., Eur. J. Biochem. 269:3409-3416 (2002). The C. limicola enzyme, encoded by aclAB, is irreversible and activity of the enzyme is regulated by the ratio of ADP/ATP. The Chlorobium tepidum a recombinant ACL from Chlorobium tepidum was also expressed in E. coli and the holoenzyme was reconstituted in vitro, in a study elucidating the role of the alpha and beta subunits in the catalytic mechanism (Kim and Tabita, J. Bacteriol. 188:6544-6552 (2006). ACL enzymes have also been identified in Balnearium lithotrophicum, Sulfurihydrogenibium subterraneum and other members of the bacterial phylum Aquificae (Hugler et al., Environ. Microbiol. 9:81-92 (2007)). This activity has been reported in some fungi as well. Exemplary organisms include Sordaria macrospora (Nowrousian et al., Curr. Genet. 37:189-93 (2000)), Aspergillus nidulans and Yarrowia lipolytica (Hynes and Murray, Eukaryotic Cell, July: 1039-1048, (2010), and Aspergillus niger (Meijer et al. J. Ind. Microbiol. Biotechnol. 36:1275-1280 (2009). Other candidates can be found based on sequence homology. Information related to these enzymes is tabulated below.

Protein GenBank ID GI Number Organism aclA BAB21376.1 12407237 Chlorobium limicola aclB BAB21375.1 12407235 Chlorobium limicola aclA AAM72321.1 21647054 Chlorobium tepidum aclB AAM72322.1 21647055 Chlorobium tepidum aclB ABI50084.1 114055039 Sulfurihydrogenibium subterraneum aclA AAX76834.1 62199504 Sulfurimonas denitrificans aclB AAX76835.1 62199506 Sulfurimonas denitrificans acl1 XP_504787.1 50554757 Yarrowia lipolytica acl2 XP_503231.1 50551515 Yarrowia lipolytica SPBC1703.07 NP_596202.1 19112994 Schizosaccharomyces pombe SPAC22A12.16 NP_593246.1 19114158 Schizosaccharomyces pombe acl1 CAB76165.1 7160185 Sordaria macrospora acl2 CAB76164.1 7160184 Sordaria macrospora aclA CBF86850.1 259487849 Aspergillus nidulans aclB CBF86848 259487848 Aspergillus nidulans

In some organisms the conversion of citrate to oxaloacetate and acetyl-CoA proceeds through a citryl-CoA intermediate and is catalyzed by two separate enzymes, citryl-CoA synthetase (EC 6.2.1.18) and citryl-CoA lyase (EC 4.1.3.34) (Aoshima, M., Appl. Microbiol. Biotechnol. 75:249-255 (2007). Citryl-CoA synthetase catalyzes the activation of citrate to citryl-CoA. The Hydrogenobacter thermophilus enzyme is composed of large and small subunits encoded by ccsA and ccsB, respectively (Aoshima et al., Mol. Micrbiol. 52:751-761 (2004)). The citryl-CoA synthetase of Aquifex aeolicus is composed of alpha and beta subunits encoded by sucC1 and sucD1 (Hugler et al., Environ. Microbiol. 9:81-92 (2007)). Citryl-CoA lyase splits citryl-CoA into oxaloacetate and acetyl-CoA. This enzyme is a homotrimer encoded by ccl in Hydrogenobacter thermophilus (Aoshima et al., Mol. Microbiol. 52:763-770 (2004)) and aq_150 in Aquifex aeolicus (Hugler et al., supra (2007)). The genes for this mechanism of converting citrate to oxaloacetate and citryl-CoA have also been reported recently in Chlorobium tepidum (Eisen et al., PNAS 99(14): 9509-14 (2002)).

Protein GenBank ID GI Number Organism ccsA BAD17844.1 46849514 Hydrogenobacter thermophilus ccsB BAD17846.1 46849517 Hydrogenobacter thermophilus sucC1 AAC07285 2983723 Aquifex aeolicus sucD1 AAC07686 2984152 Aquifex aeolicus ccl BAD17841.1 46849510 Hydrogenobacter thermophilus aq_150 AAC06486 2982866 Aquifex aeolicus CT0380 NP_661284 21673219 Chlorobium tepidum CT0269 NP_661173.1 21673108 Chlorobium tepidum CT1834 AAM73055.1 21647851 Chlorobium tepidum

Citrate lyase (EC 4.1.3.6, FIGS. 4 and 5, step E) catalyzes a series of reactions resulting in the cleavage of citrate to acetate and oxaloacetate. In certain embodiments, citrate lyase is expressed in the cytosol of a eukaryotic organism. The enzyme is active under anaerobic conditions and is composed of three subunits: an acyl-carrier protein (ACP, gamma), an ACP transferase (alpha), and an acyl lyase (beta). Enzyme activation uses covalent binding and acetylation of an unusual prosthetic group, 2′-(5″-phosphoribosyl)-3-′-dephospho-CoA, which is similar in structure to acetyl-CoA. Acylation is catalyzed by CitC, a citrate lyase synthetase. Two additional proteins, CitG and CitX, are used to convert the apo enzyme into the active holo enzyme (Schneider et al., Biochemistry 39:9438-9450 (2000)). Wild type E. coli does not have citrate lyase activity; however, mutants deficient in molybdenum cofactor synthesis have an active citrate lyase (Clark, FEMS Microbiol. Lett. 55:245-249 (1990)). The E. coli enzyme is encoded by citEFD and the citrate lyase synthetase is encoded by citC (Nilekani and SivaRaman, Biochemistry 22:4657-4663 (1983)). The Leuconostoc mesenteroides citrate lyase has been cloned, characterized and expressed in E. coli (Bekal et al., J. Bacteriol. 180:647-654 (1998)). Citrate lyase enzymes have also been identified in enterobacteria that utilize citrate as a carbon and energy source, including Salmonella typhimurium and Klebsiella pneumoniae (Bott, Arch. Microbiol. 167: 78-88 (1997); Bott and Dimroth, Mol. Microbiol. 14:347-356 (1994)). The aforementioned proteins are tabulated below.

Protein GenBank ID GI Number Organism citF AAC73716.1 1786832 Escherichia coli cite AAC73717.2 87081764 Escherichia coli citD AAC73718.1 1786834 Escherichia coli citC AAC73719.2 87081765 Escherichia coli citG AAC73714.1 1786830 Escherichia coli citX AAC73715.1 1786831 Escherichia coli citF CAA71633.1 2842397 Leuconostoc mesenteroides citE CAA71632.1 2842396 Leuconostoc mesenteroides citD CAA71635.1 2842395 Leuconostoc mesenteroides citC CAA71636.1 3413797 Leuconostoc mesenteroides citG CAA71634.1 2842398 Leuconostoc mesenteroides citX CAA71634.1 2842398 Leuconostoc mesenteroides citF NP_459613.1 16763998 Salmonella typhimurium citE AAL19573.1 16419133 Salmonella typhimurium citD NP_459064.1 16763449 Salmonella typhimurium citC NP_459616.1 16764001 Salmonella typhimurium citG NP_459611.1 16763996 Salmonella typhimurium citX NP_459612.1 16763997 Salmonella typhimurium citF CAA56217.1 565619 Klebsiella pneumoniae citE CAA56216.1 565618 Klebsiella pneumoniae citD CAA56215.1 565617 Klebsiella pneumoniae citC BAH66541.1 238774045 Klebsiella pneumoniae citG CAA56218.1 565620 Klebsiella pneumoniae citX AAL60463.1 18140907 Klebsiella pneumoniae

The acylation of acetate to acetyl-CoA is catalyzed by enzymes with acetyl-CoA synthetase activity (FIGS. 4 and 5, step F). In certain embodiments, acetyl-CoA synthetase is expressed in the cytosol of a eukaryotic organism. Two enzymes that catalyze this reaction are AMP-forming acetyl-CoA synthetase (EC 6.2.1.1) and ADP-forming acetyl-CoA synthetase (EC 6.2.1.13). AMP-forming acetyl-CoA synthetase (ACS) is the predominant enzyme for activation of acetate to acetyl-CoA. Exemplary ACS enzymes are found in E. coli (Brown et al., J. Gen. Microbiol. 102:327-336 (1977)), Ralstonia eutropha (Priefert and Steinbuchel, J. Bacteriol. 174:6590-6599 (1992)), Methanothermobacter thermautotrophicus (Ingram-Smith and Smith, Archaea 2:95-107 (2007)), Salmonella enterica (Gulick et al., Biochemistry 42:2866-2873 (2003)) and Saccharomyces cerevisiae (Jogl and Tong, Biochemistry 43:1425-1431 (2004)).

Protein GenBank ID GI Number Organism acs AAC77039.1 1790505 Escherichia coli acoE AAA21945.1 141890 Ralstonia eutropha acs1 ABC87079.1 86169671 Methanothermobacter thermautotrophicus acs1 AAL23099.1 16422835 Salmonella enterica ACS1 Q01574.2 257050994 Saccharomyces cerevisiae

ADP-forming acetyl-CoA synthetase (ACD, EC 6.2.1.13) is another candidate enzyme that couples the conversion of acyl-CoA esters to their corresponding acids with the concurrent synthesis of ATP. Several enzymes with broad substrate specificities have been described in the literature. ACD I from Archaeoglobus fulgidus, encoded by AF1211, was shown to operate on a variety of linear and branched-chain substrates including acetyl-CoA, propionyl-CoA, butyryl-CoA, acetate, propionate, butyrate, isobutyryate, isovalerate, succinate, fumarate, phenylacetate, indoleacetate (Musfeldt et al., J. Bacteriol. 184:636-644 (2002)). The enzyme from Haloarcula marismortui (annotated as a succinyl-CoA synthetase) accepts propionate, butyrate, and branched-chain acids (isovalerate and isobutyrate) as substrates, and was shown to operate in the forward and reverse directions (Brasen et al., Arch. Microbiol. 182:277-287 (2004)). The ACD encoded by PAE3250 from hyperthermophilic crenarchaeon Pyrobaculum aerophilum showed the broadest substrate range of all characterized ACDs, reacting with acetyl-CoA, isobutyryl-CoA (preferred substrate) and phenylacetyl-CoA (Brasen et al., supra (2004)). The enzymes from A. fulgidus, H. marismortui and P. aerophilum have all been cloned, functionally expressed, and characterized in E. coli (Musfeldt et al., supra; Brasen et al., supra (2004)). Additional candidates include the succinyl-CoA synthetase encoded by sucCD in E. coli (Buck et al., Biochemistry 24:6245-6252 (1985)) and the acyl-CoA ligase from Pseudomonas putida (Fernandez-Valverde et al., Appl. Environ. Microbiol. 59:1149-1154 (1993)). Information related to these proteins and genes is shown below.

Protein GenBank ID GI number Organism AF1211 NP_070039.1 11498810 Archaeoglobus fulgidus DSM 4304 AF1983 NP_070807.1 11499565 Archaeoglobus fulgidus DSM 4304 scs YP_135572.1 55377722 Haloarcula marismortui ATCC 43049 PAE3250 NP_560604.1 18313937 Pyrobaculum aerophilum str. IM2 sucC NP_415256.1 16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia coli paaF AAC24333.2 22711873 Pseudomonas putida

An alternative method for adding the CoA moiety to acetate is to apply a pair of enzymes such as a phosphate-transferring acyltransferase and an acetate kinase (FIGS. 4 and 5, Step F). This activity enables the net formation of acetyl-CoA with the simultaneous consumption of ATP. In certain embodiments, phosphotransacetylase is expressed in the cytosol of a eukaryotic organism. An exemplary phosphate-transferring acyltransferase is phosphotransacetylase, encoded by pta. The pta gene from E. coli encodes an enzyme that can convert acetyl-CoA into acetyl-phosphate, and vice versa (Suzuki, T. Biochim. Biophys. Acta 191:559-569 (1969)). This enzyme can also utilize propionyl-CoA instead of acetyl-CoA forming propionate in the process (Hesslinger et al. Mol. Microbiol 27:477-492 (1998)). Homologs exist in several other organisms including Salmonella enterica and Chlamydomonas reinhardtii.

Protein GenBank ID GI number Organism Pta NP_416800.1 16130232 Escherichia coli Pta NP_461280.1 16765665 Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 PAT2 XP_001694504.1 159472743 Chlamydomonas reinhardtii PAT1 XP_001691787.1 159467202 Chlamydomonas reinhardtii

An exemplary acetate kinase is the E. coli acetate kinase, encoded by ackA (Skarstedt and Silverstein J. Biol. Chem. 251:6775-6783 (1976)). Homologs exist in several other organisms including Salmonella enterica and Chlamydomonas reinhardtii. Information related to these proteins and genes is shown below:

Protein GenBank ID GI number Organism AckA NP_416799.1 16130231 Escherichia coli AckA NP_461279.1 16765664 Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 ACK1 XP_001694505.1 159472745 Chlamydomonas reinhardtii ACK2 XP_001691682.1 159466992 Chlamydomonas reinhardtii

In some embodiments, cytosolic oxaloacetate is transported back into a mitochondrion by an oxaloacetate transporter. Oxaloacetate transported back into a mitochondrion can then be used in the acetyl-CoA pathways described herein. Transport of oxaloacetate from the cytosol to the mitochondrion can be carried out by several transport proteins. Such proteins either import oxaloacetate directly (i.e., oxaloacetate transporter) to the mitochondrion or import oxaloacetate to the cytosol while simultaneously transporting a molecule such as citrate (i.e., citrate/oxaloacetate transporter) from the mitochondrion into the cytosol as shown in FIG. 5. Exemplary transport enzymes that carry out these transformations are provided in the table below.

Protein GenBank ID GI number Organism OAC1 NP_012802.1 6322729 Saccharomyces cerevisiae S288c KLLA0B12826g XP_452102.1 50304305 Kluyveromyces lactis NRRL Y-1140 YALI0E04048g XP_503525.1 50552101 Yarrowia lipolytica CTRG_02239 XP_002547942.1 255726032 Candida tropicalis MYA-3404 DIC1 NP_013452.1 6323381 Saccharomyces cerevisiae S288c YALI0B03344g XP_500457.1 50545838 Yarrowia lipolytica CTRG_02122 XP_002547815.1 255725772 Candida tropicalis MYA-3404 PAS_chr4_0877 XP_002494326.1 254574434 Pichia pastoris GS115 DTC CAC84549.1 19913113 Arabidopsis thaliana DTC1 CAC84545.1 19913105 Nicotiana tabacum DTC2 CAC84546.1 19913107 Nicotiana tabacum DTC3 CAC84547.1 19913109 Nicotiana tabacum DTC4 CAC84548.1 19913111 Nicotiana tabacum DTC AAR06239.1 37964368 Citrus junos

In some embodiments, cytosolic oxaloacetate is first converted to malate by a cytosolic malate dehydrogenase (FIG. 4, step H). Cytosolic malate is transported into a mitochondrion by a malate transporter or a citrate/malate transporter (FIG. 4, step I). Mitochondrial malate is then converted to oxaloacetate by a mitochondrial malate dehydrogenase (FIG. 4, step J). Mitochondrial oxaloacetate can then be used in the acetyl-CoA pathways described herein. Exemplary examples of each of these enzymes are provided below.

Oxaloacetate is converted into malate by malate dehydrogenase (EC 1.1.1.37, FIG. 4, step H). When malate is the dicarboxylate transported from the cytosol to mitochondrion, expression of both a cytosolic and mitochondrial version of malate dehydrogenase, e.g., as shown in FIG. 3, can be used. S. cerevisiae possesses three copies of malate dehydrogenase, MDH1 (McAlister-Henn and Thompson, J. Bacteriol. 169:5157-5166 (1987), MDH2 (Minard and McAlister-Henn, Mol. Cell. Biol. 11:370-380 (1991); Gibson and McAlister-Henn, J. Biol. Chem. 278:25628-25636 (2003)), and MDH3 (Steffan and McAlister-Henn, J. Biol. Chem. 267:24708-24715 (1992)), which localize to the mitochondrion, cytosol, and peroxisome, respectively. Close homologs to the cytosolic malate dehydrogenase, MDH2, from S. cerevisiae are found in several organisms including Kluyveromyces lactis and Candida tropicalis. E. coli is also known to have an active malate dehydrogenase encoded by mdh.

Protein GenBank ID GI Number Organism MDH1 NP_012838 6322765 Saccharomyces cerevisiae MDH2 NP_014515 116006499 Saccharomyces cerevisiae MDH3 NP_010205 6320125 Saccharomyces cerevisiae Mdh NP_417703.1 16131126 Escherichia coli KLLA0E07525p XP_454288.1 50308571 Kluyveromyces lactis NRRL Y-1140 YALI0D16753g XP_502909.1 50550873 Yarrowia lipolytica CTRG_01021 XP_002546239.1 255722609 Candida tropicalis MYA-3404

Transport of malate from the cytosol to the mitochondrion can be carried out by several transport proteins. Such proteins either import malate directly (i.e., malate transporter) to the mitochondrion or import malate to the cytosol while simultaneously transporting a molecule such as citrate (i.e., citrate/malate transporter) from the mitochondrion into the cytosol as shown in FIG. 4. Exemplary transport enzymes that carry out these transformations are provided in the table below.

Protein GenBank ID GI number Organism OAC1 NP_012802.1 6322729 Saccharomyces cerevisiae S288c KLLA0B12826g XP_452102.1 50304305 Kluyveromyces lactis NRRL Y-1140 YALI0E04048g XP_503525.1 50552101 Yarrowia lipolytica CTRG_02239 XP_002547942.1 255726032 Candida tropicalis MYA-3404 DIC1 NP_013452.1 6323381 Saccharomyces cerevisiae S288c YALI0B03344g XP_500457.1 50545838 Yarrowia lipolytica CTRG_02122 XP_002547815.1 255725772 Candida tropicalis MYA-3404 PAS_chr4_0877 XP_002494326.1 254574434 Pichia pastoris GS115 DTC CAC84549.1 19913113 Arabidopsis thaliana DTC1 CAC84545.1 19913105 Nicotiana tabacum DTC2 CAC84546.1 19913107 Nicotiana tabacum DTC3 CAC84547.1 19913109 Nicotiana tabacum DTC4 CAC84548.1 19913111 Nicotiana tabacum DTC AAR06239.1 37964368 Citrus junos

Malate can be converted into oxaloacetate by malate dehydrogenase (EC 1.1.1.37, FIG. 4, step J). When malate is the dicarboxylate transported from the cytosol to mitochondrion, in certain embodiments, both a cytosolic and mitochondrial version of malate dehydrogenase is expressed, as shown in FIGS. 3 and 4. S. cerevisiae possesses three copies of malate dehydrogenase, MDH1 (McAlister-Henn and Thompson, J. Bacteriol. 169:5157-5166 (1987), MDH2 (Minard and McAlister-Henn, Mol. Cell. Biol. 11:370-380 (1991); Gibson and McAlister-Henn, J. Biol. Chem. 278:25628-25636 (2003)), and MDH3 (Steffan and McAlister-Henn, J. Biol. Chem. 267:24708-24715 (1992)), which localize to the mitochondrion, cytosol, and peroxisome, respectively. Close homologs to the mitochondrial malate dehydrogenase, MDH1, from S. cerevisiae are found in several organisms including Kluyveromyces lactis, Yarrowia lipolytica, Candida tropicalis. E. coli is also known to have an active malate dehydrogenase encoded by mdh.

Protein GenBank ID GI Number Organism MDH1 NP_012838 6322765 Saccharomyces cerevisiae MDH2 NP_014515 116006499 Saccharomyces cerevisiae MDH3 NP_010205 6320125 Saccharomyces cerevisiae Mdh NP_417703.1 16131126 Escherichia coli KLLA0F25960g XP_456236.1 50312405 Kluyveromyces lactis NRRL Y-1140 YALI0D16753g XP_502909.1 50550873 Yarrowia lipolytica CTRG_00226 XP_002545445.1 255721021 Candida tropicalis MYA-3404

Example V Utilization of Pathway Enzymes with a Preference for NADH

The production of acetyl-CoA from glucose can generate at most four reducing equivalents in the form of NADH. A straightforward and energy efficient mode of maximizing the yield of reducing equivalents is to employ the Embden-Meyerhof-Parnas glycolysis pathway (EMP pathway). In many carbohydrate utilizing organisms, one NADH molecule is generated per oxidation of each glyceraldehyde-3-phosphate molecule by means of glyceraldehyde-3-phosphate dehydrogenase. Given that two molecules of glyceraldehyde-3-phosphate are generated per molecule of glucose metabolized via the EMP pathway, two NADH molecules can be obtained from the conversion of glucose to pyruvate.

Two additional molecules of NADH can be generated from conversion of pyruvate to acetyl-CoA given that two molecules of pyruvate are generated per molecule of glucose metabolized via the EMP pathway. This could be done by employing any of the following enzymes or enzyme sets to convert pyruvate to acetyl-CoA:

-   -   I. NAD-dependant pyruvate dehydrogenase;     -   II. Pyruvate formate lyase and NAD-dependant formate         dehydrogenase;     -   III. Pyruvate:ferredoxin oxidoreductase and NADH:ferredoxin         oxidoreductase;     -   IV. Pyruvate decarboxylase and an NAD-dependant acylating         acetylaldehyde dehydrogenase;     -   V. Pyruvate decarboxylase, NAD-dependant acylating acetaldehyde         dehydrogenase, acetate kinase, and phosphotransacetylase; and     -   VI. Pyruvate decarboxylase, NAD-dependant acylating acetaldehyde         dehydrogenase, and acetyl-CoA synthetase.

Overall, four molecules of NADH can be attained per glucose molecule metabolized. In one aspect, the fatty alcohol pathway requires three reduction steps from acetyl-CoA. Therefore, it can be possible that each of these three reduction steps will utilize NADPH or NADH as the reducing agents, in turn converting these molecules to NADP or NAD, respectively. Therefore, in some aspects, it can be desirable that all reduction steps are NADH-dependant in order to maximize the yield of fatty alcohols, fatty aldehydes or fatty acids. High yields of fatty alcohols, fatty aldehydes and fatty acids can thus be accomplished by:

Identifying and implementing endogenous or exogenous fatty alcohol, fatty aldehyde or fatty acid pathway enzymes with a stronger preference for NADH than other reducing equivalents such as NADPH,

-   -   I. Attenuating one or more endogenous fatty alcohol, fatty         aldehyde or fatty acid pathway enzymes that contribute         NADPH-dependant reduction activity,     -   II. Altering the cofactor specificity of endogenous or exogenous         fatty alcohol, fatty aldehyde or fatty acid pathway enzymes so         that they have a stronger preference for NADH than their natural         versions, or     -   III. Altering the cofactor specificity of endogenous or         exogenous fatty alcohol, fatty aldehyde or fatty acid pathway         enzymes so that they have a weaker preference for NADPH than         their natural versions.

The individual enzyme or protein activities from the endogenous or exogenous DNA sequences can be assayed using methods well known in the art. For example, the genes can be expressed in E. coli and the activity of their encoded proteins can be measured using cell extracts. Alternatively, the enzymes can be purified using standard procedures well known in the art and assayed for activity. Spectrophotometric based assays are particularly effective.

Several examples and methods of altering the cofactor specificity of enzymes are known in the art. For example, Khoury et al. (Protein Sci. 2009 October; 18(10): 2125-2138) created several xylose reductase enzymes with an increased affinity for NADH and decreased affinity for NADPH. Ehsani et al (Biotechnology and Bioengineering, Volume 104, Issue 2, pages 381-389, 1 Oct. 2009) drastically decreased activity of 2,3-butanediol dehydrogenase on NADH while increasing activity on NADPH. Machielsen et al (Engineering in Life Sciences, Volume 9, Issue 1, pages 38-44, February 2009) dramatically increased activity of alcohol dehydrogenase on NADH. Khoury et al (Protein Sci. 2009 October; 18(10): 2125-2138) list in Table I several previous examples of successfully changing the cofactor preference of over 25 other enzymes. Additional descriptions can be found in Lutz et al, Protein Engineering Handbook, Volume 1 and Volume 2, 2009, Wiley-VCH Verlag GmbH & Co. KGaA, in particular, Chapter 31: Altering Enzyme Substrate and Cofactor Specificity via Protein Engineering.

Example VI Determining Cofactor Preference of Pathway Enzymes

This example describes an experimental method for determining the cofactor preference of an enzyme.

Cofactor preference of enzymes for each of the pathway steps can be determined by cloning the individual genes on a plasmid behind a constitutive or inducible promoter and transforming into a host organism such as Escherichia coli. For example, genes encoding enzymes that catalyze pathway steps from: 1) acetoacetyl-CoA to 3-hydroxybutyryl-CoA, 2) 3-hydroxybutyryl-CoA to 3-hydroxybutyraldehyde, 3) 3-hydroxybutyraldehyde to 1,3-butanediol (wherein R₁ is C₁; R₃ is OH) can be assembled onto the pZ-based expression vectors as described below.

Replacement of the Stuffer Fragment in the pZ-Based Expression Vectors.

Vector backbones were obtained from Dr. Rolf Lutz of Expressys (www.expressys.de/). The vectors and strains are based on the pZ Expression System developed by Lutz and Bujard (Nucleic Acids Res 25, 1203-1210 (1997)). The pZE13luc, pZA33luc, pZS*13luc and pZE22luc contain the luciferase gene as a stuffer fragment. To replace the luciferase stuffer fragment with a lacZ-alpha fragment flanked by appropriate restriction enzyme sites, the luciferase stuffer fragment is removed from each vector by digestion with EcoRI and XbaI. The lacZ-alpha fragment is PCR amplified from pUC19 with the following primers:

lacZalpha-RI (SEQ ID NO: 1) 5′GACGAATTCGCTAGCAAGAGGAGAAGTCGACATGTCCAATTCACT GGCCGTCGTTTTAC3′ lacZalpha 3'BB (SEQ ID NO: 2) 5′-GACCCTAGGAAGCTTTCTAGAGTCGACCTATGCGGCATCAGAGCA GA-3′

This generates a fragment with a 5′ end of EcoRI site, NheI site, a Ribosomal Binding Site, a SalI site and the start codon. On the 3′ end of the fragment are the stop codon, XbaI, HindIII, and AvrII sites. The PCR product is digested with EcoRI and AvrII and ligated into the base vectors digested with EcoRI and XbaI (XbaI and AvrII have compatible ends and generate a non-site). Because NheI and XbaI restriction enzyme sites generate compatible ends that can be ligated together (but generate a site after ligation that is not digested by either enzyme), the genes cloned into the vectors can be “Biobricked” together (openwetware.org/wiki/Synthetic_Biology:BioBricks). Briefly, this method enables joining an unlimited number of genes into the vector using the same 2 restriction sites (as long as the sites do not appear internal to the genes), because the sites between the genes are destroyed after each addition. These vectors can be subsequently modified using the Phusion® Site-Directed Mutagenesis Kit (NEB, Ipswich, Mass., USA) to insert the spacer sequence AATTAA between the EcoRI and NheI sites. This eliminates a putative stem loop structure in the RNA that bound the RBS and start codon.

All vectors have the pZ designation followed by letters and numbers indicating the origin of replication, antibiotic resistance marker and promoter/regulatory unit. The origin of replication is the second letter and is denoted by E for ColE1, A for p15A and S for pSC101 (as well as a lower copy number version of pSC101 designated S*)—based origins. The first number represents the antibiotic resistance marker (1 for Ampicillin, 2 for Kanamycin, 3 for Chloramphenicol). The final number defines the promoter that regulated the gene of interest (1 for PLtetO-1, 2 for PLlacO-1 and 3 for PA1lacO-1). For the work discussed here we employed three base vectors, pZS*13S, pZA33S and pZE13S, modified for the biobricks insertions as discussed above.

Plasmids containing genes encoding pathway enzymes can then transformed into host strains containing lacIQ, which allow inducible expression by addition of isopropyl β-D-1-thiogalactopyranoside (IPTG). Activities of the heterologous enzymes are tested in in vitro assays, using strain E. coli MG1655 lacIQ as the host for the plasmid constructs containing the pathway genes. Cells can be grown aerobically in LB media (Difco) containing the appropriate antibiotics for each construct, and induced by addition of IPTG at 1 mM when the optical density (OD600) reached approximately 0.5. Cells can be harvested after 6 hours, and enzyme assays conducted as discussed below.

In Vitro Enzyme Assays.

To obtain crude extracts for activity assays, cells can be harvested by centrifugation at 4,500 rpm (Beckman-Coulter, Allegera X-15R) for 10 min. The pellets are resuspended in 0.3 mL BugBuster (Novagen) reagent with benzonase and lysozyme, and lysis proceeds for about 15 minutes at room temperature with gentle shaking Cell-free lysate is obtained by centrifugation at 14,000 rpm (Eppendorf centrifuge 5402) for 30 min at 4° C. Cell protein in the sample is determined using the method of Bradford et al., Anal. Biochem. 72:248-254 (1976), and specific enzyme assays conducted as described below. Activities are reported in Units/mg protein, where a unit of activity is defined as the amount of enzyme required to convert 1 micromol of substrate in 1 minute at room temperature.

Pathway steps can be assayed in the reductive direction using a procedure adapted from several literature sources (Durre et al., FEMS Microbiol. Rev. 17:251-262 (1995); Palosaari and Rogers, Bacteriol. 170:2971-2976 (1988) and Welch et al., Arch. Biochem. Biophys. 273:309-318 (1989). The oxidation of NADH or NADPH can be followed by reading absorbance at 340 nM every four seconds for a total of 240 seconds at room temperature. The reductive assays can be performed in 100 mM MOPS (adjusted to pH 7.5 with KOH), 0.4 mM NADH or 0.4 mM NADPH, and from 1 to 50 μmol of cell extract. For carboxylic acid reductase-like enzymes, ATP can also be added at saturating concentrations. The reaction can be started by adding the following reagents: 100 μmol of 100 mM acetoacetyl-CoA, 3-hydroxybutyryl-CoA, 3-hydroxybutyrate, or 3-hydroxybutyraldehyde. The spectrophotometer is quickly blanked and then the kinetic read is started. The resulting slope of the reduction in absorbance at 340 nM per minute, along with the molar extinction coefficient of NAD(P)H at 340 nM (6000) and the protein concentration of the extract, can be used to determine the specific activity.

Example VII Methods for Increasing NADPH Availability

In some aspects of the invention, it can be advantageous to employ pathway enzymes that have activity using NADPH as the reducing agent. For example, NADPH-dependant pathway enzymes can be highly specific for MI-FAE cycle and/or termination pathway intermediates or can possess favorable kinetic properties using NADPH as a substrate. If one or more pathway steps is NADPH dependant, several alternative approaches to increase NADPH availability can be employed. These include:

-   -   1) Increasing flux relative to wild-type through the oxidative         branch of the pentose phosphate pathway comprising         glucose-6-phosphate dehydrogenase, 6-phosphogluconolactonase,         and 6-phosphogluconate dehydrogenase (decarboxylating). This         will generate 2 NADPH molecules per glucose-6-phosphate         metabolized. However, the decarboxylation step will reduce the         maximum theoretical yield of 1,3-butanediol.     -   2) Increasing flux relative to wild-type through the Entner         Doudoroff pathway comprising glucose-6-phosphate dehydrogenase,         6-phosphogluconolactonase, phosphogluconate dehydratase, and         2-keto-3-deoxygluconate 6-phosphate aldolase.     -   3) Introducing a soluble transhydrogenase to convert NADH to         NADPH.     -   4) Introducing a membrane-bound transhydrogenase to convert NADH         to NADPH.     -   5) Employing an NADP-dependant glyceraldehyde-3-phosphate         dehydrogenase.     -   6) Employing any of the following enzymes or enzyme sets to         convert pyruvate to acetyl-CoA         -   a) NADP-dependant pyruvate dehydrogenase;         -   b) Pyruvate formate lyase and NADP-dependant formate             dehydrogenase;         -   c) Pyruvate:ferredoxin oxidoreductase and NADPH:ferredoxin             oxidoreductase;         -   d) Pyruvate decarboxylase and an NADP-dependant acylating             acetylaldehyde dehydrogenase;         -   e) Pyruvate decarboxylase, NADP-dependant acetaldehyde             dehydrogenase, acetate kinase, and phosphotransacetylase;             and         -   f) Pyruvate decarboxylase, NADP-dependant acetaldehyde             dehydrogenase, and acetyl-CoA synthetase; and optionally             attenuating NAD-dependant versions of these enzymes.     -   7) Altering the cofactor specificity of a native         glyceraldehyde-3-phosphate dehydrogenase, pyruvate         dehydrogenase, formate dehydrogenase, or acylating         acetylaldehyde dehydrogenase to have a stronger preference for         NADPH than their natural versions.     -   8) Altering the cofactor specificity of a native         glyceraldehyde-3-phosphate dehydrogenase, pyruvate         dehydrogenase, formate dehydrogenase, or acylating         acetylaldehyde dehydrogenase to have a weaker preference for         NADH than their natural versions.

The individual enzyme or protein activities from the endogenous or exogenous DNA sequences can be assayed using methods well known in the art. For example, the genes can be expressed in E. coli and the activity of their encoded proteins can be measured using cell extracts as described in the previous example. Alternatively, the enzymes can be purified using standard procedures well known in the art and assayed for activity. Spectrophotometric based assays are particularly effective.

Several examples and methods of altering the cofactor specificity of enzymes are known in the art. For example, Khoury et al (Protein Sci. 2009 October; 18(10): 2125-2138) created several xylose reductase enzymes with an increased affinity for NADH and decreased affinity for NADPH. Ehsani et al (Biotechnology and Bioengineering, Volume 104, Issue 2, pages 381-389, 1 Oct. 2009) drastically decreased activity of 2,3-butanediol dehydrogenase on NADH while increasing activity on NADPH. Machielsen et al (Engineering in Life Sciences, Volume 9, Issue 1, pages 38-44, February 2009) dramatically increased activity of alcohol dehydrogenase on NADH. Khoury et al (Protein Sci. 2009 October; 18(10): 2125-2138) list in Table I several previous examples of successfully changing the cofactor preference of over 25 other enzymes. Additional descriptions can be found in Lutz et al, Protein Engineering Handbook, Volume 1 and Volume 2, 2009, Wiley-VCH Verlag GmbH & Co. KGaA, in particular, Chapter 31: Altering Enzyme Substrate and Cofactor Specificity via Protein Engineering.

Enzyme candidates for these steps are provided below.

Glucose-6-phosphate dehydrogenase

Protein GenBank ID GI Number Organism ZWF1 NP_014158.1 6324088 Saccharomyces cerevisiae S288c ZWF1 XP_504275.1 50553728 Yarrowia lipolytica Zwf XP_002548953.1 255728055 Candida tropicalis MYA-3404 Zwf XP_001400342.1 145233939 Aspergillus niger CBS 513.88 KLLA0D19855g XP_453944.1 50307901 Kluyveromyces lactis NRRL Y-1140

6-Phosphogluconolactonase

Protein GenBank ID GI Number Organism SOL3 NP_012033.2 82795254 Saccharomyces cerevisiae S288c SOL4 NP_011764.1 6321687 Saccharomyces cerevisiae S288c YALI0E11671g XP_503830.1 50552840 Yarrowia lipolytica YALI0C19085g XP_501998.1 50549055 Yarrowia lipolytica ANI_1_656014 XP_001388941.1 145229265 Aspergillus niger CBS 513.88 CTRG_00665 XP_002545884.1 255721899 Candida tropicalis MYA-3404 CTRG_02095 XP_002547788.1 255725718 Candida tropicalis MYA-3404 KLLA0A05390g XP_451238.1 50302605 Kluyveromyces lactis NRRL Y-1140 KLLA0C08415g XP_452574.1 50305231 Kluyveromyces lactis NRRL Y-1140

6-Phosphogluconate dehydrogenase (decarboxylating)

Protein GenBank ID GI Number Organism GND1 NP_012053.1 6321977 Saccharomyces cerevisiae S288c GND2 NP_011772.1 6321695 Saccharomyces cerevisiae S288c ANI_1_282094 XP_001394208.2 317032184 Aspergillus niger CBS 513.88 ANI_1_2126094 XP_001394596.2 317032939 Aspergillus niger CBS 513.88 YALI0B15598g XP_500938.1 50546937 Yarrowia lipolytica CTRG_03660 XP_002549363.1 255728875 Candida tropicalis MYA-3404 KLLA0A09339g XP_451408.1 50302941 Kluyveromyces lactis NRRL Y-1140

Phosphogluconate dehydratase

Protein GenBank ID GI Number Organism Edd AAC74921.1 1788157 Escherichia coli K-12 MG1655 Edd AAG29866.1 11095426 Zymomonas mobilis subsp. mobilis ZM4 Edd YP_350103.1 77460596 Pseudomonas fluorescens Pf0-1 ANI_1_2126094 XP_001394596.2 317032939 Aspergillus niger CBS 513.88 YALI0B15598g XP_500938.1 50546937 Yarrowia lipolytica CTRG_03660 XP_002549363.1 255728875 Candida tropicalis MYA-3404 KLLA0A09339g XP_451408.1 50302941 Kluyveromyces lactis NRRL Y-1140

2-Keto-3-deoxygluconate 6-phosphate aldolase

Protein GenBank ID GI Number Organism Eda NP_416364.1 16129803 Escherichia coli K-12 MG1655 Eda Q00384.2 59802878 Zymomonas mobilis subsp. mobilis ZM4 Eda ABA76098.1 77384585 Pseudomonas fluorescens Pf0-1

Soluble transhydrogenase

Protein GenBank ID GI Number Organism SthA NP_418397.2 90111670 Escherichia coli K-12 MG1655 SthA YP_002798658.1 226943585 Azotobacter vinelandii DJ SthA O05139.3 11135075 Pseudomonas fluorescens

Membrane-bound transhydrogenase

Protein GenBank ID GI Number Organism ANI_1_29100 XP_001400109.2 317027842 Aspergillus niger CBS 513.88 Pc21g18800 XP_002568871.1 226943585 255956237 Penicillium chrysogenum Wisconsin 54-1255 SthA O05139.3 11135075 Pseudomonas fluorescens NCU01140 XP_961047.2 164426165 Neurospora crassa OR74A

NADP-dependant glyceraldehyde-3-phosphate dehydrogenase

Protein GenBank ID GI Number Organism gapN AAA91091.1 642667 Streptococcus mutans NP-GAPDH AEC07555.1 330252461 Arabidopsis thaliana GAPN AAM77679.2 82469904 Triticum aestivum gapN CAI56300.1 87298962 Clostridium acetobutylicum NADP-GAPDH 2D2I_A 112490271 Synechococcus elongatus PCC 7942 NADP-GAPDH CAA62619.1 4741714 Synechococcus elongatus PCC 7942 GDP1 XP_455496.1 50310947 Kluyveromyces lactis NRRL Y-1140 HP1346 NP_208138.1 15645959 Helicobacter pylori 26695

NAD-dependant glyceraldehyde-3-phosphate dehydrogenase

Protein GenBank ID GI Number Organism TDH1 NP_012483.1 6322409 Saccharomyces cerevisiae s288c TDH2 NP_012542.1 6322468 Saccharomyces cerevisiae s288c TDH3 NP_011708.1 632163 Saccharomyces cerevisiae s288c KLLA0A11858g XP_451516.1 50303157 Kluyveromyces lactis NRRL Y-1140 KLLA0F20988g XP_456022.1 50311981 Kluyveromyces lactis NRRL Y-1140 ANI_1_256144 XP_001397496.1 145251966 Aspergillus niger CBS 513.88 YALI0C06369g XP_501515.1 50548091 Yarrowia lipolytica CTRG_05666 XP_002551368.1 255732890 Candida tropicalis MYA-3404

Mutated LpdA from E. coli K-12 MG1655 described in Biochemistry, 1993, 32 (11), pp 2737-2740:

(SEQ ID NO: 3) MSTEIKTQVVVLGAGPAGYSAAFRCADLGLETVIVERYNTLGGVCLN VGCIPSKALLHVAKVIEEAKALAEHGIVFGEPKTDIDKIRTWKEKVI NQLTGGLAGMAKGRKVKVVNGLGKFTGANTLEVEGENGKTVINFDNA IIAAGSRPIQLPFIPHEDPRIWDSTDALELKEVPERLLVMGGGIIGL EMGTVYHALGSQIDVVVRKHQVIRAADKDIVKVFTKRISKKFNLMLE TKVTAVEAKEDGIYVTMEGKKAPAEPQRYDAVLVAIGRVPNGKNLDA GKAGVEVDDRGFIRVDKQLRTNVPHIFAIGDIVGQPMLAHKGVHEGH VAAEVIAGKKHYFDPKVIPSIAYTEPEVAWVGLTEKEAKEKGISYET ATFPWAASGRAIASDCADGMTKLIFDKESHRVIGGAIVGTNGGELLG EIGLAIEMGCDAEDIALTIHAHPTLHESVGLAAEVFEGSITDLPNPK AKKK

Mutated LpdA from E. coli K-12 MG1655 described in Biochemistry, 1993, 32 (11), pp 2737-2740:

(SEQ ID NO: 4) MSTEIKTQVVVLGAGPAGYSAAFRCADLGLETVIVERYNTLGGVCLNV GCIPSKALLHVAKVIEEAKALAEHGIVFGEPKTDIDKIRTWKEKVINQ LTGGLAGMAKGRKVKVVNGLGKFTGANTLEVEGENGKTVINFDNAIIA AGSRPIQLPFIPHEDPRIWDSTDALELKEVPERLLVMGGGIIALEMAT VYHALGSQIDVVVRKHQVIRAADKDIVKVFTKRISKKFNLMLETKVTA VEAKEDGIYVTMEGKKAPAEPQRYDAVLVAIGRVPNGKNLDAGKAGVE VDDRGFIRVDKQLRTNVPHIFAIGDIVGQPMLAHKGVHEGHVAAEVIA GKKHYFDPKVIPSIAYTEPEVAWVGLTEKEAKEKGISYETATFPWAAS GRAIASDCADGMTKLIFDKESHRVIGGAIVGTNGGELLGEIGLAIEMG CDAEDIALTIHAHPTLHESVGLAAEVFEGSITDLPNPKAKKK

NADP-dependent formate dehydrogenase

Protein GenBank ID GI Number Organism fdh ACF35003. 194220249 Burkholderia stabilis fdh ABC20599.2 146386149 Moorella thermoacetica ATCC 39073

Mutant Candida bodinii enzyme described in Journal of Molecular Catalysis B: Enzymatic, Volume 61, Issues 3-4, December 2009, Pages 157-161:

(SEQ ID NO: 5) MKIVLVLYDAGKHAADEEKLYGCTENKLGIANWLKDQGHELITTSDKE GETSELDKHIPDADIIITTPFHPAYITKERLDKAKNLKLVVVAGVGSD HIDLDYINQTGKKISVLEVTGSNVVSVAEHVVMTMLVLVRNFVPAHEQ IINHDWEVAAIAKDAYDIEGKTIATIGAGRIGYRVLERLLPFNPKELL YYQRQALPKEAEEKVGARRVENIEELVAQADIVTVNAPLHAGTKGLIN KELLSKFKKGAWLVNTARGAICVAEDVAAALESGQLRGYGGDVWFPQP APKDHPWRDMRNKYGAGNAMTPHYSGTTLDAQTRYAEGTKNILESFFT GKFDYRPQDIILLNGEYVTKAYGKHDKK

Mutant Candida bodinii enzyme described in Journal of Molecular Catalysis B: Enzymatic, Volume 61, Issues 3-4, December 2009, Pages 157-161:

(SEQ ID NO: 6) MKIVLVLYDAGKHAADEEKLYGCTENKLGIANWLKDQGHELITTSDKE GETSELDKHIPDADIIITTPFHPAYITKERLDKAKNLKLVVVAGVGSD HIDLDYINQTGKKISVLEVTGSNVVSVAEHVVMTMLVLVRNFVPAHEQ IINHDWEVAAIAKDAYDIEGKTIATIGAGRIGYRVLERLLPFNPKELL YYSPQALPKEAEEKVGARRVENIEELVAQADIVTVNAPLHAGTKGLIN KELLSKFKKGAWLVNTARGAICVAEDVAAALESGQLRGYGGDVWFPQP APKDHPWRDMRNKYGAGNAMTPHYSGTTLDAQTRYAEGTKNILESFFT GKFDYRPQDIILLNGEYVTKAYGKHDKK

Mutant Saccharomyces cerevisiae enzyme described in Biochem J. 2002 November 1:367(Pt. 3):841-847:

(SEQ ID NO: 7) MSKGKVLLVLYEGGKHAEEQEKLLGCIENELGIRNFIEEQGYELVTTI DKDPEPTSTVDRELKDAEIVITTPFFPAYISRNRIAEAPNLKLCVTAG VGSDHVDLEAANERKITVTEVTGSNVVSVAEHVMATILVLIRNYNGGH QQAINGEWDIAGVAKNEYDLEDKIISTVGAGRIGYRVLERLVAFNPKK LLYYARQELPAEAINRLNEASKLFNGRGDIVQRVEKLEDMVAQSDVVT INCPLHKDSRGLFNKKLISHMKDGAYLVNTARGAICVAEDVAEAVKSG KLAGYGGDVWDKQPAPKDHPWRTMDNKDHVGNAMTVHISGTSLDAQKR YAQGVKNILNSYFSKKFDYRPQDIIVQNGSYATRAYGQKK.

NADPH: ferredoxin oxidoreductase

Protein GenBank ID GI Number Organism petH YP_171276.1 56750575 Synechococcus elongatus PCC 6301 fpr NP_457968.1 16762351 Salmonella enterica fnr1 XP_001697352.1 159478523 Chlamydomonas reinhardtii rfnr1 NP_567293.1 18412939 Arabidopsis thaliana aceF NP_414657.1 6128108 Escherichia coli K-12 MG1655

NADP-dependent acylating acetylaldehyde dehydrogenase

Protein GenBank ID GI Number Organism adhB AAB06720.1 1513071 Thermoanaerobacter pseudethanolicus ATCC 33223 TheetDRAFT_0840 ZP_08211603. 326390041 Thermoanaerobacter ethanolicus JW 200 Cbei_3832 YP_001310903.1 150018649 Clostridium beijerinckii NCIMB 8052 Cbei_4054 YP_001311120.1 150018866 Clostridium beijerinckii NCIMB 8052 Cbei_4045 YP_001311111.1 150018857 Clostridium beijerinckii NCIMB 8052

Exemplary genes encoding pyruvate dehydrogenase, pyruvate:ferredoxin oxidoreductase, pyruvate formate lyase, pyruvate decarboxylase, acetate kinase, phosphotransacetylase and acetyl-CoA synthetase are described above in Example II.

Example VIII Engineering Saccharomyces cerevisiae for Chemical Production

Eukaryotic hosts have several advantages over prokaryotic systems. They are able to support post-translational modifications and host membrane-anchored and organelle-specific enzymes. Genes in eukaryotes typically have introns, which can impact the timing of gene expression and protein structure.

An exemplary eukaryotic organism well suited for industrial chemical production is Saccharomyces cerevisiae. This organism is well characterized, genetically tractable and industrially robust. Genes can be readily inserted, deleted, replaced, overexpressed or underexpressed using methods known in the art. Some methods are plasmid-based whereas others modify the chromosome (Guthrie and Fink. Guide to Yeast Genetics and Molecular and Cell Biology, Part B, Volume 350, Academic Press (2002); Guthrie and Fink, Guide to Yeast Genetics and Molecular and Cell Biology, Part C, Volume 351, Academic Press (2002)).

Plasmid-mediated gene expression is enabled by yeast episomal plasmids (YEps). YEps allow for high levels of expression; however they are not very stable and they require cultivation in selective media. They also have a high maintenance cost to the host metabolism. High copy number plasmids using auxotrophic (e.g., URA3, TRP1, HIS3, LEU2) or antibiotic selectable markers (e.g., Zeo^(R) or Kan^(R)) can be used, often with strong, constitutive promoters such as PGK1 or ACT1 and a transcription terminator-polyadenylation region such as those from CYC1 or AOX. Many examples are available for one well-versed in the art. These include pVV214 (a 2 micron plasmid with URA3 selectable marker) and pVV200 (2 micron plasmid with TRP1 selectable marker) (Van et al., Yeast 20:739-746 (2003)). Alternatively, low copy plasmids such as centromeric or CEN plamids can be used. Again, many examples are available for one well-versed in the art. These include pRS313 and pRS315 (Sikorski and Hieter, Genetics 122:19-27 (1989) both of which require that a promoter (e.g., PGK1 or ACT1) and a terminator (e.g., CYC1, AOX) are added.

For industrial applications, chromosomal overexpression of genes is preferable to plasmid-mediated overexpression. Mikkelsen and coworkers have identified 11 integration sites on highly expressed regions of the S. cerevisiae genome on chromosomes X, XI and XII (Mikkelsen et al, Met Eng 14:104-11 (2012)). The sites are separated by essential genes, minimizing the possibility of recombination between sites.

Tools for inserting genes into eukaryotic organisms such as S. cerevisiae are known in the art. Particularly useful tools include yeast integrative plasmids (YIps), yeast artificial chromosomes (YACS) and gene targeting/homologous recombination. Note that these tools can also be used to insert, delete, replace, underexpress or otherwise alter the genome of the host.

Yeast integrative plasmids (YIps) utilize the native yeast homologous recombination system to efficiently integrate DNA into the chromosome. These plasmids do not contain an origin of replication and can therefore only be maintained after chromosomal integration. An exemplary construct includes a promoter, the gene of interest, a terminator, and a selectable marker with a promoter, flanked by FRT sites, loxP sites, or direct repeats enabling the removal and recycling of the resistance marker. The method entails the synthesis and amplification of the gene of interest with suitable primers, followed by the digestion of the gene at a unique restriction site, such as that created by the EcoRI and XhoI enzymes (Vellanki et al., Biotechnol Lett. 29:313-318 (2007)). The gene of interest is inserted at the EcoRI and XhoI sites into a suitable expression vector, downstream of the promoter. The gene insertion is verified by PCR and DNA sequence analysis. The recombinant plasmid is then linearized and integrated at a desired site into the chromosomal DNA of S. cerevisiae using an appropriate transformation method. The cells are plated on the YPD medium with an appropriate selection marker and incubated for 2-3 days. The transformants are analyzed for the requisite gene insert by colony PCR. To remove the antibiotic marker from a construct flanked by loxP sites, a plasmid containing the Cre recombinase is introduced. Cre recombinase promotes the excision of sequences flanked by loxP sites. (Gueldener et al., Nucleic Acids Res 30:e23 (2002)). The resulting strain is cured of the Cre plasmid by successive culturing on media without any antibiotic present. Alternately, the Cre recombinase plasmid has a URA selection marker and the plasmid is efficiently removed by growing cells on 5-FOA which acts as a counter-selection for URA. This method can also be employed for a scarless integration instead of using loxP. One skilled in the art can integrate using URA as a marker, select for integration by growing on URA-minus plates, and then select for URA mutants by growing on 5-FOA plates. 5-FOA is converted to the toxic 5-fluoruracil by the URA gene product. Alternatively, the FLP-FRT system can be used to integrate genes into the chromosome. This system involves the recombination of sequences between short Flipase Recognition Target (FRT) sites by the Flipase recombination enzyme (FLP) derived from the 2μ plasmid of the yeast Saccharomyces cerevisiae (Sadowski, P. D., Prog. Nucleic. Acid. Res. Mol. Biol. 51:53-91 (1995); Zhu and Sadowski J. Biol. Chem. 270:23044-23054 (1995)). Similarly, gene deletion methodologies will be carried out as described in refs. Baudin et al. Nucleic. Acids Res. 21:3329-3330 (1993); Brachmann et al., Yeast 14:115-132 (1998); Giaever et al., Nature 418:387-391 (2002); Longtine et al., Yeast 14:953-961 (1998) Winzeler et al., Science 285:901-906 (1999).

Another approach for manipulating the yeast chromosome is gene targeting. This approach takes advantage of the fact that double stranded DNA breaks in yeast are repaired by homologous recombination. Linear DNA fragments flanked by targeting sequences can thus be efficiently integrated into the yeast genome using the native homologous recombination machinery. In addition to the application of inserting genes, gene targeting approaches are useful for genomic DNA manipulations such as deleting genes, introducing mutations in a gene, its promoter or other regulatory elements, or adding a tag to a gene.

Yeast artificial chromosomes (YACs) are artificial chromosomes useful for pathway construction and assembly. YACs enable the expression of large sequences of DNA (100-3000 kB) containing multiple genes. The use of YACs was recently applied to engineer flavenoid biosynthesis in yeast (Naesby et al, Microb Cell Fact 8:49-56 (2009)). In this approach, YACs were used to rapidly test randomly assembled pathway genes to find the best combination.

The expression level of a gene can be modulated by altering the sequence of a gene and/or its regulatory regions. Such gene regulatory regions include, for example, promoters, enhancers, introns, and terminators. Functional disruption of negative regulatory elements such as repressors and/or silencers also can be employed to enhance gene expression. RNA based tools can also be employed to regulate gene expression. Such tools include RNA aptamers, riboswitches, antisense RNA, ribozymes and riboswitches.

For altering a gene's expression by its promoter, libraries of constitutive and inducible promoters of varying strengths are available. Strong constitutive promoters include pTEF1, pADH1 and promoters derived from glycolytic pathway genes. The pGAL promoters are well-studied inducible promoters activated by galactose and repressed by glucose. Another commonly used inducible promoter is the copper inducible promoter pCUP1 (Farhi et al, Met Eng 13:474-81 (2011)). Further variation of promoter strengths can be introduced by mutagenesis or shuffling methods. For example, error prone PCR can be applied to generate synthetic promoter libraries as shown by Alper and colleagues (Alper et al, PNAS 102:12678-83 (2005)). Promoter strength can be characterized by reporter proteins such as beta-galactosidase, fluorescent proteins and luciferase.

The placement of an inserted gene in the genome can alter its expression level. For example, overexpression of an integrated gene can be achieved by integrating the gene into repeating DNA elements such as ribosomal DNA or long terminal repeats.

For exogenous expression in yeast or other eukaryotic cells, genes can be expressed in the cytosol without the addition of leader sequence, or can be targeted to mitochondrion or other organelles, or targeted for secretion, by the addition of a suitable targeting sequence such as a mitochondrial targeting or secretion signal suitable for the host cells. Thus, it is understood that appropriate modifications to a nucleic acid sequence to remove or include a targeting sequence can be incorporated into an exogenous nucleic acid sequence to impart desirable properties. Genetic modifications can also be made to enhance polypeptide synthesis. For example, translation efficiency is enhanced by substituting ribosome binding sites with an optimal or consensus sequence and/or altering the sequence of a gene to add or remove secondary structures. The rate of translation can also be increased by substituting one coding sequence with another to better match the codon preference of the host.

Example IX Termination Pathways for Making Fatty Alcohols, Aldehydes and Acids

This example describes enzymes for converting intermediates of the MI-FAE cycle to products of interest such as fatty alcohols, fatty aldehydes, and fatty acids. Pathways are shown in FIGS. 1 and 7. Enzymes for catalyzing steps A-G are disclosed in Example I. This example describes enzymes suitable for catalyzing steps H-N.

Enzymes include: A. Thiolase, B. 3-Ketoacyl-CoA reductase, C. β-Hydroxyl-ACP dehydratase, D. Enoyl-CoA reductase, E. Acyl-CoA reductase (aldehyde forming), F. Alcohol dehydrogenase, G. Acyl-CoA reductase (alcohol forming), H. acyl-CoA hydrolase, transferase or synthetase, J. Acyl-ACP reductase, K. Acyl-CoA:ACP acyltransferase, L. Thioesterase, N. Aldehyde dehydrogenase (acid forming) or carboxylic acid reductase.

Pathways for converting an MI-FAE cycle intermediate to an fatty alcohol, fatty aldehyde or fatty acid product are shown in the table below. These pathways are also referred to herein as “termination pathways”.

Termination pathway Product enzymes from FIG. 1 Acid H K/L E/N K/J/N Aldehyde E K/J H/N K/L/N Alcohol E/F K/J/F H/N/F K/L/N/F G

Product specificity can be fine-tuned using one or more enzymes shown in FIGS. 1 and 6. Chain length is controlled by one or more enzymes of the elongation pathway in conjunction with one more enzymes of the termination pathway as described above. The structure of the product is controlled by one or more enzymes of the termination pathway. Examples of selected termination pathway enzymes reacting with various pathway intermediates are shown in the table below. Additional examples are described herein.

Enzyme Substrate Example Acyl-CoA reductase Acyl-CoA Acr1 of A. bayliyi (GenBank AAC45217) 3-Hydroxyacyl-CoA PduP of L. reuteri (GenBank CCC03595.1) 3-Oxoacyl-CoA Mcr of S. tokodaii (GenBank NP_378167) Acyl-CoA hydrolase, Acyl-CoA tesB of E. coli transferase (GenBank NP_414986) or synthetase 3-Hydroxyacyl-CoA hibch of R. norvegicus (GenBank Q5XIE6.2) 3-Oxoacyl-CoA MKS2 of S. lycopersicum (GenBank ACG69783) Enoyl-CoA gctAB of Acidaminococcus fermentans(GenBank CAA57199, CAA57200) Acyl-ACP Acyl-CoA fabH of E. coli acyltransferase (GenBank AAC74175.1)

Step H. Acyl-CoA Hydrolase, Transferase or Synthase

Acyl-CoA hydrolase, transferase and synthase enzymes convert acyl-CoA moieties to their corresponding acids. Such an enzyme can be utilized to convert, for example, a fatty acyl-CoA to a fatty acid, a 3-hydroxyacyl-CoA to a 3-hydroxyacid, a 3-oxoacyl-CoA to a 3-oxoacid, or an enoyl-CoA to an enoic acid.

CoA hydrolase or thioesterase enzymes in the 3.1.2 family hydrolyze acyl-CoA molecules to their corresponding acids. Several CoA hydrolases with different substrate ranges are suitable for hydrolyzing acyl-CoA, 3-hydroxyacyl-CoA, 3-oxoacyl-CoA and enoyl-CoA substrates to their corresponding acids. For example, the enzyme encoded by acot12 from Rattus norvegicus brain (Robinson et al., Biochem. Biophys. Res. Commun. 71:959-965 (1976)) can react with butyryl-CoA, hexanoyl-CoA and malonyl-CoA. The human dicarboxylic acid thioesterase, encoded by acot8, exhibits activity on glutaryl-CoA, adipyl-CoA, suberyl-CoA, sebacyl-CoA, and dodecanedioyl-CoA (Westin et al., J. Biol. Chem. 280:38125-38132 (2005)). The closest E. coli homolog to this enzyme, tesB, can also hydrolyze a range of CoA thiolesters (Naggert et al., J Biol Chem 266:11044-11050 (1991)). A similar enzyme has also been characterized in the rat liver (Deana R., Biochem Int 26:767-773 (1992)). Additional enzymes with hydrolase activity in E. coli include ybgC, paaI, and ybdB (Kuznetsova, et al., FEMS Microbiol Rev, 2005, 29(2):263-279; Song et al., J Biol Chem, 2006, 281(16):11028-38). Though its sequence has not been reported, the enzyme from the mitochondrion of the pea leaf has a broad substrate specificity, with demonstrated activity on acetyl-CoA, propionyl-CoA, butyryl-CoA, palmitoyl-CoA, oleoyl-CoA, succinyl-CoA, and crotonyl-CoA (Zeiher et al., Plant. Physiol. 94:20-27 (1990)) The acetyl-CoA hydrolase, ACH1, from S. cerevisiae represents another candidate hydrolase (Buu et al., J. Biol. Chem. 278:17203-17209 (2003)). Additional enzymes with aryl-CoA hydrolase activity include the palmitoyl-CoA hydrolase of Mycobacterium tuberculosis (Wang et al., Chem. Biol. 14:543-551 (2007)) and the acyl-CoA hydrolase of E. coli encoded by entH (Guo et al., Biochemistry 48:1712-1722 (2009)). Additional CoA hydrolase enzymes are described above.

GenBank Gene name Accession # GI# Organism acot12 NP_570103.1 18543355 Rattus norvegicus tesB NP_414986 16128437 Escherichia coli acot8 CAA15502 3191970 Homo sapiens acot8 NP_570112 51036669 Rattus norvegicus tesA NP_415027 16128478 Escherichia coli ybgC NP_415264 16128711 Escherichia coli paaI NP_415914 16129357 Escherichia coli ybdB NP_415129 16128580 Escherichia coli ACH1 NP_009538 6319456 Saccharomyces cerevisiae Rv0098 NP_214612.1 15607240 Mycobacterium tuberculosis entH AAC73698.1 1786813 Escherichia coli

CoA hydrolase enzymes active on 3-hydroxyacyl-CoA, 3-oxoacyl-CoA and enoyl-CoA intermediates are also well known in the art. For example, an enzyme for converting enoyl-CoA substrates to their corresponding acids is the glutaconate CoA-transferase from Acidaminococcus fermentans. This enzyme was transformed by site-directed mutagenesis into an acyl-CoA hydrolase with activity on glutaryl-CoA, acetyl-CoA and 3-butenoyl-CoA (Mack et al., FEBS. Lett. 405:209-212 (1997)). Another suitable enzyme is the fadM thioesterase III of E. coli. This enzyme is involved in oleate beta-oxidation and the preferred substrate is 3,5-tetradecadienoyl-CoA (Nie et al, Biochem 47:7744-51 (2008)).

Protein GenBank ID GI Number Organism gctA CAA57199.1 559392 Acidaminococcus fermentans gctB CAA57200.1 559393 Acidaminococcus fermentans gctA ACJ24333.1 212292816 Clostridium symbiosum gctB ACJ24326.1 212292808 Clostridium symbiosum gctA NP_603109.1 19703547 Fusobacterium nucleatum gctB NP_603110.1 19703548 Fusobacterium nucleatum fadM NP_414977.1 16128428 Escherichia coli

3-Hydroxyisobutyryl-CoA hydrolase is active on 3-hydroxyacyl-CoA substrates (Shimomura et al., J Biol Chem. 269:14248-14253 (1994)). Genes encoding this enzyme include hibch of Rattus norvegicus (Shimomura et al., Methods Enzymol. 324:229-240 (2000)) and Homo sapiens (Shimomura et al., supra). Similar gene candidates can also be identified by sequence homology, including hibch of Saccharomyces cerevisiae and BC 2292 of Bacillus cereus. An exemplary 3-oxoacyl-CoA hydrolase is MKS2 of Solanum lycopersicum (Yu et al, Plant Physiol 154:67-77 (2010)). The native substrate of this enzyme is 3-oxo-myristoyl-CoA, which produces a C14 chain length product.

GenBank Gene name Accession # GI# Organism fadM NP_414977.1 16128428 Escherichia coli hibch Q5XIE6.2 146324906 Rattus norvegicus hibch Q6NVY1.2 146324905 Homo sapiens hibch P28817.2 2506374 Saccharomyces cerevisiae BC_2292 AP09256 29895975 Bacillus cereus MKS2 ACG69783.1 196122243 Solarium lycopersicum

CoA transferases catalyze the reversible transfer of a CoA moiety from one molecule to another. Several transformations require a CoA transferase to activate carboxylic acids to their corresponding acyl-CoA derivatives. CoA transferase enzymes have been described in the open literature and represent suitable candidates for these steps. These are described below.

The gene products of cat1, cat2, and cat3 of Clostridium kluyveri have been shown to exhibit succinyl-CoA, 4-hydroxybutyryl-CoA, and butyryl-CoA transferase activity, respectively (Seedorf et al., Proc. Natl. Acad. Sci U.S.A. 105:2128-2133 (2008); Sohling et al., J Bacteriol. 178:871-880 (1996)). Similar CoA transferase activities are also present in Trichomonas vaginalis, Trypanosoma brucei, Clostridium aminobutyricum and Porphyromonas gingivalis (Riviere et al., J. Biol. Chem. 279:45337-45346 (2004); van Grinsven et al., J. Biol. Chem. 283:1411-1418 (2008)).

Protein GenBank ID GI Number Organism cat1 P38946.1 729048 Clostridium kluyveri cat2 P38942.2 172046066 Clostridium kluyveri cat3 EDK35586.1 146349050 Clostridium kluyveri TVAG_395550 XP_001330176 123975034 Trichomonas vaginalis G3 Tb11.02.0290 XP_828352 71754875 Trypanosoma brucei cat2 CAB60036.1 6249316 Clostridium aminobutyricum cat2 NP_906037.1 34541558 Porphyromonas gingivalis W83

A fatty acyl-CoA transferase that utilizes acetyl-CoA as the CoA donor is acetoacetyl-CoA transferase, encoded by the E. coli atoA (alpha subunit) and atoD (beta subunit) genes (Korolev et al., Acta Crystallogr. D. Biol. Crystallogr. 58:2116-2121 (2002); Vanderwinkel et al., 33:902-908 (1968)). This enzyme has a broad substrate range on substrates of chain length C3-C6 (Sramek et al., Arch Biochem Biophys 171:14-26 (1975)) and has been shown to transfer the CoA moiety to acetate from a variety of branched and linear 3-oxo and acyl-CoA substrates, including isobutyrate (Matthies et al., Appl Environ. Microbiol 58:1435-1439 (1992)), valerate (Vanderwinkel et al., Biochem. Biophys. Res. Commun. 33:902-908 (1968)) and butanoate (Vanderwinkel et al., Biochem. Biophys. Res. Commun. 33:902-908 (1968)). This enzyme is induced at the transcriptional level by acetoacetate, so modification of regulatory control may be necessary for engineering this enzyme into a pathway (Pauli et al., Eur. J Biochem. 29:553-562 (1972)). Similar enzymes exist in Corynebacterium glutamicum ATCC 13032 (Duncan et al., 68:5186-5190 (2002)), Clostridium acetobutylicum (Cary et al., Appl Environ Microbiol 56:1576-1583 (1990); Wiesenborn et al., Appl Environ Microbiol 55:323-329 (1989)), and Clostridium saccharoperbutylacetonicum (Kosaka et al., Biosci. Biotechnol Biochem. 71:58-68 (2007)).

Gene GI # Accession No. Organism atoA 2492994 P76459.1 Escherichia coli atoD 2492990 P76458.1 Escherichia coli actA 62391407 YP_226809.1 Corynebacterium glutamicum cg0592 62389399 YP_224801.1 Corynebacterium glutamicum ctfA 15004866 NP_149326.1 Clostridium acetobutylicum ctfB 15004867 NP_149327.1 Clostridium acetobutylicum ctfA 31075384 AAP42564.1 Clostridium saccharoperbutylacetonicum ctfB 31075385 AAP42565.1 Clostridium saccharoperbutylacetonicum

Beta-ketoadipyl-CoA transferase, also known as succinyl-CoA:3:oxoacid-CoA transferase, is active on 3-oxoacyl-CoA substrates. This enzyme is encoded by pcaI and pcaJ in Pseudomonas putida (Kaschabek et al., J. Bacteriol. 184:207-215 (2002)). Similar enzymes are found in Acinetobacter sp. ADP1 (Kowalchuk et al., Gene 146:23-30 (1994)), Streptomyces coelicolor and Pseudomonas knackmussii (formerly sp. B13) (Gobel et al., J Bacteriol. 184:216-223 (2002); Kaschabek et al., J Bacteriol. 184:207-215 (2002)). Additional exemplary succinyl-CoA:3:oxoacid-CoA transferases have been characterized in Helicobacter pylori (Corthesy-Theulaz et al., J Biol. Chem. 272:25659-25667 (1997)), Bacillus subtilis (Stols et al., Protein Expr. Purif. 53:396-403 (2007)) and Homo sapiens (Fukao, T., et al., Genomics 68:144-151 (2000); Tanaka, H., et al., Mol Hum Reprod 8:16-23 (2002)). Genbank information related to these genes is summarized below.

Gene GI # Accession No. Organism pcaI 24985644 AAN69545.1 Pseudomonas putida pcaJ 26990657 NP_746082.1 Pseudomonas putida pcaI 50084858 YP_046368.1 Acinetobacter sp. ADP1 pcaJ 141776 AAC37147.1 Acinetobacter sp. ADP1 pcaI 21224997 NP_630776.1 Streptomyces coelicolor pcaJ 21224996 NP_630775.1 Streptomyces coelicolor catI 75404583 Q8VPF3 Pseudomonas knackmussii catJ 75404582 Q8VPF2 Pseudomonas knackmussii HPAG1_0676 108563101 YP_627417 Helicobacter pylori HPAG1_0677 108563102 YP_627418 Helicobacter pylori ScoA 16080950 NP_391778 Bacillus subtilis ScoB 16080949 NP_391777 Bacillus subtilis OXCT1 NP_000427 4557817 Homo sapiens OXCT2 NP_071403 11545841 Homo sapiens

The conversion of acyl-CoA substrates to their acid products can be catalyzed by a CoA acid-thiol ligase or CoA synthetase in the 6.2.1 family of enzymes. CoA synthases that convert ATP to ADP (ADP-forming) are reversible and react in the direction of acid formation, whereas AMP forming enzymes only catalyze the activation of an acid to an acyl-CoA. For fatty acid formation, deletion or attenuation of AMP forming enzymes will reduce backflux. ADP-forming acetyl-CoA synthetase (ACD, EC 6.2.1.13) is an enzyme that couples the conversion of acyl-CoA esters to their corresponding acids with the concomitant synthesis of ATP. ACD I from Archaeoglobus fulgidus, encoded by AF1211, was shown to operate on a variety of linear and branched-chain substrates including isobutyrate, isopentanoate, and fumarate (Musfeldt et al., J Bacteriol. 184:636-644 (2002)). A second reversible ACD in Archaeoglobus fulgidus, encoded by AF1983, was also shown to have a broad substrate range (Musfeldt and Schonheit, J Bacteriol. 184:636-644 (2002)). The enzyme from Haloarcula marismortui (annotated as a succinyl-CoA synthetase) accepts propionate, butyrate, and branched-chain acids (isovalerate and isobutyrate) as substrates, and was shown to operate in the forward and reverse directions (Brasen et al., Arch Microbiol 182:277-287 (2004)). The ACD encoded by PAE3250 from hyperthermophilic crenarchaeon Pyrobaculum aerophilum showed the broadest substrate range of all characterized ACDs, reacting with acetyl-CoA, isobutyryl-CoA (preferred substrate) and phenylacetyl-CoA (Brasen et al, supra). Directed evolution or engineering can be used to modify this enzyme to operate at the physiological temperature of the host organism. The enzymes from A. fulgidus, H. marismortui and P. aerophilum have all been cloned, functionally expressed, and characterized in E. coli (Brasen and Schonheit, supra; Musfeldt and Schonheit, J Bacteriol. 184:636-644 (2002)). An additional candidate is succinyl-CoA synthetase, encoded by sucCD of E. coli and LSC1 and LSC2 genes of Saccharomyces cerevisiae. These enzymes catalyze the formation of succinyl-CoA from succinate with the concomitant consumption of one ATP in a reaction which is reversible in vivo (Buck et al., Biochemistry 24:6245-6252 (1985)). The acyl CoA ligase from Pseudomonas putida has been demonstrated to work on several aliphatic substrates including acetic, propionic, butyric, valeric, hexanoic, heptanoic, and octanoic acids and on aromatic compounds such as phenylacetic and phenoxyacetic acids (Fernandez-Valverde et al., Appl. Environ. Microbiol. 59:1149-1154 (1993)). A related enzyme, malonyl CoA synthetase (6.3.4.9) from Rhizobium leguminosarum could convert several diacids, namely, ethyl-, propyl-, allyl-, isopropyl-, dimethyl-, cyclopropyl-, cyclopropylmethylene-, cyclobutyl-, and benzyl-malonate into their corresponding monothioesters (Pohl et al., J. Am. Chem. Soc. 123:5822-5823 (2001)).

Protein GenBank ID GI Number Organism AF1211 NP_070039.1 11498810 Archaeoglobus fulgidus AF1983 NP_070807.1 11499565 Archaeoglobus fulgidus scs YP_135572.1 55377722 Haloarcula marismortui PAE3250 NP_560604.1 18313937 Pyrobaculum aerophilum str. IM2 sucC NP_415256.1 16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia coli LSC1 NP_014785 6324716 Saccharomyces cerevisiae LSC2 NP_011760 6321683 Saccharomyces cerevisiae paaF AAC24333.2 22711873 Pseudomonas putida matB AAC83455.1 3982573 Rhizobium leguminosarum

Step J. Acyl-ACP Reductase

The reduction of an acyl-ACP to its corresponding aldehyde is catalyzed by an acyl-ACP reductase (AAR). Such a transformation is depicted in step J of FIGS. 1 and 7. Suitable enzyme candidates include the orf1594 gene product of Synechococcus elongatus PCC7942 and homologs thereof (Schirmer et al, Science, 329: 559-62 (2010)). The S. elongates PCC7942 acyl-ACP reductase is coexpressed with an aldehyde decarbonylase in an operon that appears to be conserved in a majority of cyanobacterial organisms. This enzyme, expressed in E. coli together with the aldehyde decarbonylase, conferred the ability to produce alkanes. The P. marinus AAR was also cloned into E. coli and, together with a decarbonylase, demonstrated to produce alkanes (US Application 2011/0207203).

Protein GenBank ID GI Number Organism orf1594 YP_400611.1 81300403 Synechococcus elongatus PCC7942 PMT9312_0533 YP_397030.1 78778918 Prochlorococcus marinus MIT 9312 syc0051_d YP_170761.1 56750060 Synechococcus elongatus PCC 6301 Ava_2534 YP_323044.1 75908748 Anabaena variabilis ATCC 29413 alr5284 NP_489324.1 17232776 Nostoc sp. PCC 7120 Aazo_3370 YP_003722151.1 298491974 Nostoc azollae Cyan7425_0399 YP_002481152.1 220905841 Cyanothece sp. PCC 7425 N9414_21225 ZP_01628095.1 119508943 Nodularia spumigena CCY9414 L8106_07064 ZP_01619574.1 119485189 Lyngbya sp. PCC 8106

Step K. Acyl-CoA:ACP Acyltransferase

The transfer of an acyl-CoA to an acyl-ACP is catalyzed by acyltransferase enzymes in EC class 2.3.1. Enzymes with this activity are described above.

Step L. Thioesterase

Acyl-ACP thioesterase enzymes convert an acyl-ACP to its corresponding acid. Such a transformation is required in step L of FIG. 1. Exemplary enzymes include the FatA and FatB isoforms of Arabidopsis thaliana (Salas et al, Arch Biochem Biophys 403:25-34 (2002)). The activities of these two proteins vary with carbon chain length, with FatA preferring oleyl-ACP and FatB preferring palmitoyl-ACP. A number of thioesterases with different chain length specificities are listed in WO 2008/113041 and are included in the table below. For example, it has been shown previously that expression of medium chain plant thioesterases like FatB from Umbellularia californica in E. coli results in accumulation of high levels of medium chain fatty acids, primarily laurate (C12:0). Similarly, expression of Cuphea palustris FatB1 thioesterase in E. coli led to accumulation of C8-10:0 products (Dehesh et al, Plant Physiol 110:203-10 (1996)). Similarly, Carthamus tinctorius thioesterase expressed in E. coli leads to >50 fold elevation in C 18:1 chain termination and release as free fatty acid (Knutzon et al, Plant Physiol 100:1751-58 (1992)). Methods for altering the substrate specificity of thioesterases are also known in the art (for example, EP1605048).

Protein GenBank ID GI Number Organism fatA AEE76980.1 332643459 Arabidopsis thaliana fatB AEE28300.1 332190179 Arabidopsis thaliana fatB2 AAC49269.1 1292906 Cuphea hookeriana fatB3 AAC72881.1 3859828 Cuphea hookeriana fatB1 AAC49179.1 1215718 Cuphea palustris M96568.1: AAA33019.1 404026 Carthamus tinctorius 94 . . . 1251 fatB1 Q41635.1 8469218 Umbellularia californica tesA AAC73596.1 1786702 Escherichia coli

Step N. Aldehyde Dehydrogenase (Acid Forming) or Carboxylic Acid Reductase

The conversion of an aldehyde to an acid is catalyzed by an acid-forming aldehyde dehydrogenase. Several Saccharomyces cerevisiae enzymes catalyze the oxidation of aldehydes to acids including ALD1 (ALD6), ALD2 and ALD3 (Navarro-Avino et al, Yeast 15:829-42 (1999); Quash et al, Biochem Pharmacol 64:1279-92 (2002)). The mitochondrial proteins ALD4 and ALD5 catalyze similar transformations (Wang et al, J Bacteriol 180:822-30 (1998); Boubekeur et al, Eur J Biochem 268:5057-65 (2001)). HFD1 encodes a hexadecanal dehydrogenase. Exemplary acid-forming aldehyde dehydrogenase enzymes are listed in the table below.

Protein GenBank ID GI number Organism ALD2 NP_013893.1 6323822 Saccharomyces cerevisiae s288c ALD3 NP_013892.1 6323821 Saccharomyces cerevisiae s288c ALD4 NP_015019.1 6324950 Saccharomyces cerevisiae s288c ALD5 NP_010996.2 330443526 Saccharomyces cerevisiae s288c ALD6 NP_015264.1 6325196 Saccharomyces cerevisiae s288c HFD1 NP_013828.1 6323757 Saccharomyces cerevisiae s288c CaO19.8361 XP_710976.1 68490403 Candida albicans CaO19.742 XP_710989.1 68490378 Candida albicans YALI0C03025 CAG81682.1 49647250 Yarrowia lipolytica ANI_1_1334164 XP_001398871.1 145255133 Aspergillus niger ANI_1_2234074 XP_001392964.2 317031176 Aspergillus niger ANI_1_226174 XP_001402476.1 145256256 Aspergillus niger ALDH P41751.1 1169291 Aspergillus niger KLLA0D09999 CAH00602.1 49642640 Kluyveromyces lactis

The conversion of an acid to an aldehyde is thermodynamically unfavorable and typically requires energy-rich cofactors and multiple enzymatic steps. For example, in butanol biosynthesis conversion of butyrate to butyraldehyde is catalyzed by activation of butyrate to its corresponding acyl-CoA by a CoA transferase or ligase, followed by reduction to butyraldehyde by a CoA-dependent aldehyde dehydrogenase. Alternately, an acid can be activated to an acyl-phosphate and subsequently reduced by a phosphate reductase. Direct conversion of the acid to aldehyde by a single enzyme is catalyzed by a bifunctional carboxylic acid reductase enzyme in the 1.2.1 family. Exemplary enzymes that catalyze these transformations include carboxylic acid reductase, alpha-aminoadipate reductase and retinoic acid reductase.

Carboxylic acid reductase (CAR), found in Nocardia iowensis, catalyzes the magnesium, ATP and NADPH-dependent reduction of carboxylic acids to their corresponding aldehydes (Venkitasubramanian et al., J Biol. Chem. 282:478-485 (2007)). The natural substrate of this enzyme is benzoic acid and the enzyme exhibits broad acceptance of aromatic and aliphatic substrates including fatty acids of length C12-C18 (Venkitasubramanian et al., Biocatalysis in Pharmaceutical and Biotechnology Industries. CRC press (2006); WO 2010/135624). CAR requires post-translational activation by a phosphopantetheine transferase (PPTase) that converts the inactive apo-enzyme to the active holo-enzyme (Hansen et al., Appl. Environ. Microbiol 75:2765-2774 (2009)). The Nocardia CAR enzyme was cloned and functionally expressed in E. coli (Venkitasubramanian et al., J Biol. Chem. 282:478-485 (2007)). Co-expression of the npt gene, encoding a specific PPTase, improved activity of the enzyme. A related enzyme from Mycobacterium sp. strain JLS catalyzes the reduction of fatty acids of length C12-C16. Variants of this enzyme with enhanced activity on fatty acids are described in WO 2010/135624. Alpha-aminoadipate reductase (AAR, EC 1.2.1.31), participates in lysine biosynthesis pathways in some fungal species. This enzyme naturally reduces alpha-aminoadipate to alpha-aminoadipate semialdehyde. The carboxyl group is first activated through the ATP-dependent formation of an adenylate that is then reduced by NAD(P)H to yield the aldehyde and AMP. Like CAR, this enzyme utilizes magnesium and requires activation by a PPTase. Enzyme candidates for AAR and its corresponding PPTase are found in Saccharomyces cerevisiae (Morris et al., Gene 98:141-145 (1991)), Candida albicans (Guo et al., Mol. Genet. Genomics 269:271-279 (2003)), and Schizosaccharomyces pombe (Ford et al., Curr. Genet. 28:131-137 (1995)). The AAR from S. pombe exhibited significant activity when expressed in E. coli (Guo et al., Yeast 21:1279-1288 (2004)). The AAR from Penicillium chrysogenum accepts S-carboxymethyl-L-cysteine as an alternate substrate, but did not react with adipate, L-glutamate or diaminopimelate (Hijarrubia et al., J Biol. Chem. 278:8250-8256 (2003)). The gene encoding the P. chrysogenum PPTase has not been identified to date and no high-confidence hits were identified by sequence comparison homology searching.

Protein GenBank ID GI Number Organism car AAR91681.1 40796035 Nocardia iowensis npt ABI83656.1 114848891 Nocardia iowensis car YP_001070587.1 126434896 Mycobacterium sp. strain JLS npt YP_001070355.1 126434664 Mycobacterium sp. strain JLS LYS2 AAA34747.1 171867 Saccharomyces cerevisiae LYS5 P50113.1 1708896 Saccharomyces cerevisiae LYS2 AAC02241.1 2853226 Candida albicans LYS5 AAO26020.1 28136195 Candida albicans Lys1p P40976.3 13124791 Schizosaccharomyces pombe Lys7p Q10474.1 1723561 Schizosaccharomyces pombe Lys2 CAA74300.1 3282044 Penicillium chrysogenum

Additional car and npt genes can be identified based on sequence homology.

GenBank Gene name GI No. Accession No. Organism fadD9 121638475 YP_978699.1 Mycobacterium bovis BCG BCG_2812c 121638674 YP_978898.1 Mycobacterium bovis BCG nfa20150 54023983 YP_118225.1 Nocardia farcinica IFM 10152 nfa40540 54026024 YP_120266.1 Nocardia farcinica IFM 10152 SGR_6790 YP_001828302.1 182440583 Streptomyces griseus subsp. griseus NBRC 13350 SGR_665 YP_001822177.1 182434458 Streptomyces griseus subsp. griseus NBRC 13350 MSMEG_2956 YP_887275.1 118473501 Mycobacterium smegmatis MC2 155 MSMEG_5739 YP_889972.1 118469671 Mycobacterium smegmatis MC2 155 MSMEG_2648 YP_886985.1 118471293 Mycobacterium smegmatis MC2 155 MAP1040c NP_959974.1 41407138 Mycobacterium avium subsp. paratuberculosis K-10 MAP2899c NP_961833.1 41408997 Mycobacterium avium subsp. paratuberculosis K-10 MMAR_2117 YP_001850422.1 183982131 Mycobacterium marinum M MMAR_2936 YP_001851230.1 183982939 Mycobacterium marinum M MMAR_1916 YP_001850220.1 183981929 Mycobacterium marinum M Tpau_1373 YP_003646340.1 296139097 Tsukamurella paurometabola DSM 20162 Tpau_1726 YP_003646683.1 296139440 Tsukamurella paurometabola DSM 20162 CPCC7001_1320 ZP_05045132.1 254431429 Cyanobium PCC7001 DDBDRAFT_0187729 XP_636931.1 66806417 Dictyostelium discoideum AX4

An additional enzyme candidate found in Streptomyces griseus is encoded by the griC and griD genes. This enzyme is believed to convert 3-amino-4-hydroxybenzoic acid to 3-amino-4-hydroxybenzaldehyde as deletion of either griC or griD led to accumulation of extracellular 3-acetylamino-4-hydroxybenzoic acid, a shunt product of 3-amino-4-hydroxybenzoic acid metabolism (Suzuki, et al., J. Antibiot. 60(6):380-387 (2007)). Co-expression of griC and griD with SGR_665, an enzyme similar in sequence to the Nocardia iowensis npt, can be beneficial.

GenBank Gene name GI No. Accession No. Organism griC YP_001825755.1 182438036 Streptomyces griseus subsp. griseus NBRC 13350 griD YP_001825756.1 182438037 Streptomyces griseus subsp. griseus NBRC 13350

Throughout this application various publications have been referenced. The disclosures of these publications in their entireties, including GenBank and GI number publications, are hereby incorporated by reference in this application in order to more fully describe the state of the art to which this invention pertains. Although the invention has been described with reference to the examples provided above, it should be understood that various modifications can be made without departing from the spirit of the invention. 

What is claimed is:
 1. A non-naturally occurring microbial organism for production of a compound of Formula (VI), (X) or (XIV):

wherein at least 80% of the compound produced by the microbial organism is C₇ linear alkyl at R₁, wherein the microbial organism comprises a malonyl-CoA independent fatty acyl-CoA elongation (MI-FAE) cycle and a termination pathway, wherein said MI-FAE cycle comprises one or more thiolase, one or more 3-oxoacyl-CoA reductase, one or more 3-hydroxyacyl-CoA dehydratase, and one or more enoyl-CoA reductase, wherein said termination pathway comprises a pathway selected from: (1) 1H; (2) 1K and 1L; (3) 1E and 1N; (4) 1K, 1J, and 1N; (5) 1E; (6) 1K and 1J; (7) 1H and 1N; (8) 1K, 1L, and 1N; (9) 1E and 1F; (10) 1K, 1J, and 1F; (11) 1H, 1N, and 1F; (12) 1K, 1L, 1N, and 1F; and (13) 1G, wherein 1E is an acyl-CoA reductase (aldehyde forming), wherein 1F is an alcohol dehydrogenase, wherein 1G is an acyl-CoA reductase (alcohol forming), wherein 1H is an acyl-CoA hydrolase, acyl-CoA transferase or acyl-CoA synthase, wherein 1J is an acyl-ACP reductase, wherein 1K is an acyl-CoA:ACP acyltransferase, wherein 1L is a thioesterase, wherein 1N is an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce the compound of Formula (VI), (X) or (XIV), wherein one or more enzymes of the MI-FAE cycle are each independently selective for a compound of Formula (II), propionyl-CoA or acetyl-CoA as a substrate:

wherein R_(1a) is no greater than C₇ linear alkyl R₃ is H, OH, or oxo (═O); R₄ is S-CoA; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; and wherein one or more enzymes of the termination pathway are each independently selective for the compound of Formula (II) as a substrate wherein: R_(1a) is no less than C₇ linear alkyl; R₃ is H; and R₄ is S-CoA, ACP, OH or H.
 2. A non-naturally occurring microbial organism for production of a compound of Formula (VI), (X) or (XIV):

wherein at least 80% of the compound produced by the microbial organism is C₉ linear alkyl at R₁, wherein the microbial organism comprises a malonyl-CoA independent fatty acyl-CoA elongation (MI-FAE) cycle and a termination pathway, wherein said MI-FAE cycle comprises one or more thiolase, one or more 3-oxoacyl-CoA reductase, one or more 3-hydroxyacyl-CoA dehydratase, and one or more enoyl-CoA reductase, wherein said termination pathway comprises a pathway selected from: (1) 1H; (2) 1K and 1L; (3) 1E and 1N; (4) 1K, 1J, and 1N; (5) 1E; (6) 1K and 1J; (7) 1H and 1N; (8) 1K, 1L, and 1N; (9) 1E and 1F; (10) 1K, 1J, and 1F; (11) 1H, 1N, and 1F; (12) 1K, 1L, 1N, and 1F; and (13) 1G, wherein 1E is an acyl-CoA reductase (aldehyde forming), wherein 1F is an alcohol dehydrogenase, wherein 1G is an acyl-CoA reductase (alcohol forming), wherein 1H is an acyl-CoA hydrolase, acyl-CoA transferase or acyl-CoA synthase, wherein 1J is an acyl-ACP reductase, wherein 1K is an acyl-CoA:ACP acyltransferase, wherein 1L is a thioesterase, wherein 1N is an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce the compound of Formula (VI), (X) or (XIV), wherein one or more enzymes of the MI-FAE cycle are each independently selective for a compound of Formula (II), propionyl-CoA or acetyl-CoA as a substrate:

wherein R_(1a) is no greater than C₉ linear alkyl; R₃ is H, OH, or oxo (═O); R₄ is S-CoA; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; and wherein one or more enzymes of the termination pathway are each independently selective for the compound of Formula (II) as a substrate wherein: R_(1a) is no less than C₉ linear alkyl; R₃ is H; and R₄ is S-CoA, ACP, OH or H.
 3. A non-naturally occurring microbial organism for production of a compound of Formula (VI), (X) or (XIV):

wherein at least 80% of the compound produced by the microbial organism is C₁₁ linear alkyl at R₁, wherein the microbial organism comprises a malonyl-CoA independent fatty acyl-CoA elongation (MI-FAE) cycle and a termination pathway, wherein said MI-FAE cycle comprises one or more thiolase, one or more 3-oxoacyl-CoA reductase, one or more 3-hydroxyacyl-CoA dehydratase, and one or more enoyl-CoA reductase, wherein said termination pathway comprises a pathway selected from: (1) 1H; (2) 1K and 1L; (3) 1E and 1N; (4) 1K, 1J, and 1N; (5) 1E; (6) 1K and 1J; (7) 1H and 1N; (8) 1K, 1L, and 1N; (9) 1E and 1F; (10) 1K, 1J, and 1F; (11) 1H, 1N, and 1F; (12) 1K, 1L, 1N, and 1F; and (13) 1G, wherein 1E is an acyl-CoA reductase (aldehyde forming), wherein 1F is an alcohol dehydrogenase, wherein 1G is an acyl-CoA reductase (alcohol forming), wherein 1H is an acyl-CoA hydrolase, acyl-CoA transferase or acyl-CoA synthase, wherein 1J is an acyl-ACP reductase, wherein 1K is an acyl-CoA:ACP acyltransferase, wherein 1L is a thioesterase, wherein 1N is an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce the compound of Formula (VI), (X) or (XIV), wherein one or more enzymes of the MI-FAE cycle are each independently selective for a compound of Formula (II), propionyl-CoA or acetyl-CoA as a substrate:

wherein R_(1a) is no greater than C₁₁ linear alkyl; R₃ is H, OH, or oxo (═O); R₄ is S-CoA; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; and wherein one or more enzymes of the termination pathway are each independently selective for the compound of Formula (II) as a substrate wherein: R_(1a) is no less than C₁₁ linear alkyl; R₃ is H; and R₄ is S-CoA, ACP, OH or H.
 4. A non-naturally occurring microbial organism for production of a compound of Formula (VI), (X) or (XIV):

wherein at least 80% of the compound produced by the microbial organism is C₁₃ linear alkyl at R₁, wherein the microbial organism comprises a malonyl-CoA independent fatty acyl-CoA elongation (MI-FAE) cycle and a termination pathway, wherein said MI-FAE cycle comprises one or more thiolase, one or more 3-oxoacyl-CoA reductase, one or more 3-hydroxyacyl-CoA dehydratase, and one or more enoyl-CoA reductase, wherein said termination pathway comprises a pathway selected from: (1) 1H; (2) 1K and 1L; (3) 1E and 1N; (4) 1K, 1J, and 1N; (5) 1E; (6) 1K and 1J; (7) 1H and 1N; (8) 1K, 1L, and 1N; (9) 1E and 1F; (10) 1K, 1J, and 1F; (11) 1H, 1N, and 1F; (12) 1K, 1L, 1N, and 1F; and (13) 1G, wherein 1E is an acyl-CoA reductase (aldehyde forming), wherein 1F is an alcohol dehydrogenase, wherein 1G is an acyl-CoA reductase (alcohol forming), wherein 1H is an acyl-CoA hydrolase, acyl-CoA transferase or acyl-CoA synthase, wherein 1J is an acyl-ACP reductase, wherein 1K is an acyl-CoA:ACP acyltransferase, wherein 1L is a thioesterase, wherein 1N is an aldehyde dehydrogenase (acid forming) or a carboxylic acid reductase, wherein an enzyme of the MI-FAE cycle or termination pathway is encoded by at least one exogenous nucleic acid and is expressed in a sufficient amount to produce the compound of Formula (VI), (X) or (XIV), wherein one or more enzymes of the MI-FAE cycle are each independently selective for a compound of Formula (II), propionyl-CoA or acetyl-CoA as a substrate:

wherein R_(1a) is no greater than C₁₃ linear alkyl; R₃ is H, OH, or oxo (═O); R₄ is S-CoA; and

represents a single or double bond with the proviso that the valency of the carbon atom to which R₃ is attached is four; and wherein one or more enzymes of the termination pathway are each independently selective for the compound of Formula (II) as a substrate wherein: R_(1a) is no less than C₁₃ linear alkyl; R₃ is H; and R₄ is S-CoA, ACP, OH or H.
 5. The non-naturally occurring microbial organism of claim 1, wherein at least 85%, 90%, or 95% of the compound produced by the microbial organism is C₇ linear alkyl at R₁.
 6. The non-naturally occurring microbial organism of claim 2, wherein at least 85%, 90%, or 95% of the compound produced by the microbial organism is C₉, linear alkyl at R₁.
 7. The non-naturally occurring microbial organism of claim 3, wherein at least 85%, 90%, or 95% of the compound produced by the microbial organism is C₁₁, linear alkyl at R₁.
 8. The non-naturally occurring microbial organism of claim 4, wherein at least 85%, 90%, or 95% of the compound produced by the microbial organism is C₁₃, linear alkyl at R₁.
 9. The non-naturally occurring microbial organism of any one of claims 1, 2, 3, or 4, wherein said microbial organism comprises: (a) two, three, or four exogenous nucleic acids each encoding an enzyme of said MI-FAE cycle; (b) two, three, or four exogenous nucleic acids each encoding an enzyme of said termination pathway; or (c) exogenous nucleic acids encoding each of the enzymes of at least one of the pathways selected from (1)-(13).
 10. The non-naturally occurring microbial organism of any one of claims 1, 2, 3, or 4, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.
 11. The non-naturally occurring microbial organism of any one of claims 1, 2, 3, or 4, wherein said microbial organism further comprises an acetyl-CoA pathway and at least one exogenous nucleic acid encoding an acetyl-CoA pathway enzyme expressed in a sufficient amount to produce acetyl-CoA, wherein said acetyl-CoA pathway comprises a pathway selected from: (1) 2A and 2B; (2) 2A, 2C, and 2D; (3) 2H; (4) 2G and 2D; (5) 2E, 2F and 2B; (6) 2E and 2I; (7) 2J, 2F and 2B; (8) 2J and 2I; (9) 3A, 3B, and 3C; (10) 3A, 3B, 3J, 3K, and 3D; (11) 3A, 3B, 3G, and 3D; (12) 3A, 3F, and 3D; (13) 3N, 3H, 3B and 3C; (14) 3N, 3H, 3B, 3J, 3K, and 3D; (15) 3N, 3H, 3B, 3G, and 3D; (16) 3N, 3H, 3F, and 3D; (17) 3L, 3M, 3B and 3C; (18) 3L, 3M, 3B, 3J, 3K, and 3D; (19) 3L, 3M, 3B, 3G, and 3D; (20) 3L, 3M, 3F, and 3D; (21) 4A, 4B, 4D, 4H, 4I, and 4J; (22) 4A, 4B, 4E, 4F, 4H, 4I, and 4J; (23) 4A, 4B, 4E, 4K, 4L, 4H, 4I, and 4J; (24) 4A, 4C, 4D, 4H, and 4J; (25) 4A, 4C, 4E, 4F, 4H, and 4J; (26) 4A, 4C, 4E, 4K, 4L, 4H, and 4J; (27) 5A, 5B, 5D, and 5G; (28) 5A, 5B, 5E, 5F, and 5G; (29) 5A, 5B, 5E, 5K, 5L, and 5G; (30) 5A, 5C, and 5D; (31) 5A, 5C, 5E, and 5F; and (32) 5A, 5C, 5E, 5K, and 5L, wherein 2A is a pyruvate oxidase (acetate-forming), wherein 2B is an acetyl-CoA synthetase, an acetyl-CoA ligase or an acetyl-CoA transferase, wherein 2C is an acetate kinase, wherein 2D is a phosphotransacetylase, wherein 2E is a pyruvate decarboxylase, wherein 2F is an acetaldehyde dehydrogenase, wherein 2G is a pyruvate oxidase (acetyl-phosphate forming), wherein 2H is a pyruvate dehydrogenase, a pyruvate:ferredoxin oxidoreductase, a pyruvate:NAD(P)H oxidoreductase or a pyruvate formate lyase, wherein 2I is an acetaldehyde dehydrogenase (acylating), wherein 2J is a threonine aldolase, wherein 3A is a phosphoenolpyruvate (PEP) carboxylase or a PEP carboxykinase, wherein 3B is an oxaloacetate decarboxylase, wherein 3C is a malonate semialdehyde dehydrogenase (acetylating), wherein 3D is an acetyl-CoA carboxylase or a malonyl-CoA decarboxylase, wherein 3F is an oxaloacetate dehydrogenase or an oxaloacetate oxidoreductase, wherein 3G is a malonate semialdehyde dehydrogenase (acylating), wherein 3H is a pyruvate carboxylase, wherein 3J is a malonate semialdehyde dehydrogenase, wherein 3K is a malonyl-CoA synthetase or a malonyl-CoA transferase, wherein 3L is a malic enzyme, wherein 3M is a malate dehydrogenase or a malate oxidoreductase, wherein 3N is a pyruvate kinase or a PEP phosphatase, wherein 4A is a citrate synthase, wherein 4B is a citrate transporter, wherein 4C is a citrate/malate transporter, wherein 4D is an ATP citrate lyase, wherein 4E is a citrate lyase, wherein 4F is an acetyl-CoA synthetase or an acetyl-CoA transferase, wherein 4H is a cytosolic malate dehydrogenase, wherein 4I is a malate transporter, wherein 4J is a mitochondrial malate dehydrogenase, wherein 4K is an acetate kinase, wherein 4L is a phosphotransacetylase, wherein 5A is a citrate synthase, wherein 5B is a citrate transporter, wherein 5C is a citrate/oxaloacetate transporter, wherein 5D is an ATP citrate lyase, wherein 5E is a citrate lyase, wherein 5F is an acetyl-CoA synthetase or an acetyl-CoA transferase, wherein 5G is an oxaloacetate transporter, wherein 5K is an acetate kinase, and wherein 5L is a phosphotransacetylase.
 12. The non-naturally occurring microbial organism of any one of claims 1, 2, 3, or 4, wherein the microbial organism further comprises: (a) one or more gene disruptions, said one or more gene disruptions occurring in endogenous genes encoding proteins or enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO₂, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by said microbial organism, wherein said one or more gene disruptions confer increased production of the compound of Formula (VI), (X) or (XIV) in said microbial organism; (b) one or more gene disruptions occurring in genes encoding proteins or enzymes that result in an increased ratio of NAD(P)H to NAD(P) present in the cytosol of said microbial organism following said disruptions: (c) one or more endogenous enzymes involved in: native production of ethanol, glycerol, acetate, formate, lactate, CO2, fatty acids, or malonyl-CoA by said microbial organism; transfer of pathway intermediates to cellular compartments other than the cytosol; or native degradation of a MI-FAE cycle intermediate or a termination pathway intermediate by said microbial organism, has attenuated enzyme activity or expression levels; (d) one or more endogenous enzymes involved in the oxidation of NAD(P)H or NADH, has attenuated enzyme activity or expression levels; (e) one or more enzymes of the MI-FAE cycle or the termination pathway preferentially react with an NADH cofactor or have reduced preference for reacting with an NAD(P)H cofactor, wherein said one or more enzymes of the MI-FAE cycle are a 3-ketoacyl-CoA reductase or an enoyl-CoA reductase, and wherein said one or more enzymes of the termination pathway are selected from an acyl-CoA reductase (aldehyde forming), an alcohol dehydrogenase, an acyl-CoA reductase (alcohol forming), an aldehyde decarbonylase, an acyl-ACP reductase, an aldehyde dehydrogenase (acid forming) and a carboxylic acid reductase; or (f) at least one exogenous nucleic acid encoding an extracellular transporter or an extracellular transport system for the compound of Formula (VI), (X) or (XIV).
 13. The non-naturally occurring microbial organism of any one of claims 1, 2, 3, or 4, wherein said microbial organism is Crabtree positive and is in culture medium comprising excess glucose, thereby increasing the ratio of NAD(P)H to NAD(P) present in the cytosol of said microbial organism.
 14. A method for producing the compound of Formula (VI), (X) or (XIV) comprising culturing the non-naturally occurring microbial organism of any one of claims 1, 2, 3, or 4 under conditions and for a sufficient period of time to produce said compound of Formula (VI), (X) or (XIV). 